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1
Zhang, Xufeng, Chang-Ling Zou, Liang Jiang y Hong X. Tang. "Cavity magnomechanics". Science Advances 2, n.º 3 (marzo de 2016): e1501286. http://dx.doi.org/10.1126/sciadv.1501286.
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A dielectric body couples with electromagnetic fields through radiation pressure and electrostrictive forces, which mediate phonon-photon coupling in cavity optomechanics. In a magnetic medium, according to the Korteweg-Helmholtz formula, which describes the electromagnetic force density acting on a medium, magneostrictive forces should arise and lead to phonon-magnon interaction. We report such a coupled phonon-magnon system based on ferrimagnetic spheres, which we term as cavity magnomechanics, by analogy to cavity optomechanics. Coherent phonon-magnon interactions, including electromagnetically induced transparency and absorption, are demonstrated. Because of the strong hybridization of magnon and microwave photon modes and their high tunability, our platform exhibits new features including parametric amplification of magnons and phonons, triple-resonant photon-magnon-phonon coupling, and phonon lasing. Our work demonstrates the fundamental principle of cavity magnomechanics and its application as a new information transduction platform based on coherent coupling between photons, phonons, and magnons.
2
Dovlatova, Alla y Dmitri Yerchuck. "Quantum Field Theory of Dynamics of Spectroscopic Transitions by Strong Dipole-Photon and Dipole-Phonon Coupling". ISRN Optics 2012 (12 de diciembre de 2012): 1–10. http://dx.doi.org/10.5402/2012/390749.
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Matrix-operator difference-differential equations for dynamics of spectroscopic transitions in 1D multiqubit exchange-coupled (para)magnetic and optical systems by strong dipole-photon and dipole-phonon coupling are derived within the framework of quantum field theory. It has been established that by strong dipole-photon and dipole-phonon coupling the formation of long-lived coherent system of the resonance phonons takes place, and relaxation processes acquire pure quantum character. It is determined by the appearance of coherent emission process of EM-field energy, for which the resonance phonon system is responsible. Emission process is accompanied by phonon Rabi quantum oscillation, which can be time-shared from photon quantum Rabi oscillations, accompanying coherent absorption process of EM-field energy. For the case of radio spectroscopy, it corresponds to the possibility of the simultaneous observation along with (para)magntic spin resonance, the acoustic spin resonance.
3
P, Munkhbaatar. "Generation and Detection of Squeezed Phonon". Физик сэтгүүл 22, n.º 449 (13 de marzo de 2022): 7–10. http://dx.doi.org/10.22353/physics.v22i449.595.
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The variance of the time dependent atomic positions and momenta is directly mapped into the quantum uctuations of the photon number of the scattered probing light. A fully quantum de-scription of the non-linear interactions between photonic and phononic fields unveils evidences of squeezing of thermal phonons. In here a pump-probe spectroscopy was proposed to observe phonon squeezing in solids. Numerical simulation showed pump-probe response due to coherent phonon and squeezed phonon in alpha-quartz.
4
Prasher, Ravi S. "Mie Scattering Theory for Phonon Transport in Particulate Media". Journal of Heat Transfer 126, n.º 5 (1 de octubre de 2004): 793–804. http://dx.doi.org/10.1115/1.1795243.
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Scattering theory for the scattering of phonons by particulate scatterers is developed in this paper. Recently the author introduced the generalized equation of phonon radiative transport (GEPRT) in particulate media, which included a phase function to account for the anisotropic scattering of phonons by particulate scatterer. Solution of the GEPRT showed that scattering cross section is different from the thermal transport cross-section. In this paper formulations for the scattering and transport cross section for horizontally shear (SH) wave phonon or transverse wave phonon without mode conversion is developed. The development of the theory of scattering and the transport cross section is exactly analogous to the Mie scattering theory for photon transport in particulate media. Results show that transport cross section is very different from the scattering cross section. The theory of phonon scattering developed in this paper will be useful for the predictive modeling of thermal conductivity of practical systems, such as nanocomposites, nano-micro-particle-laden systems, etc.
5
Le Dé, Brieuc, Christian J. Eckhardt, Dante M. Kennes y Michael A. Sentef. "Cavity engineering of Hubbard U via phonon polaritons". Journal of Physics: Materials 5, n.º 2 (1 de abril de 2022): 024006. http://dx.doi.org/10.1088/2515-7639/ac618e.
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Abstract Pump-probe experiments have suggested the possibility to control electronic correlations by driving infrared-active (IR-active) phonons with resonant midinfrared laser pulses. In this work we study two possible microscopic nonlinear electron-phonon interactions behind these observations, namely coupling of the squared lattice displacement either to the electronic density or to the double occupancy. We investigate whether photon-phonon coupling to quantized light in an optical cavity enables similar control over electronic correlations. We first show that inside a dark cavity electronic interactions increase, ruling out the possibility that T c in superconductors can be enhanced via effectively decreased electron-electron repulsion through nonlinear electron-phonon coupling in a cavity. We further find that upon driving the cavity, electronic interactions decrease. Two different regimes emerge: (i) a strong coupling regime where the phonons show a delayed response at a time proportional to the inverse coupling strength, and (ii) an ultra-strong coupling regime where the response is immediate when driving the phonon polaritons resonantly. We further identify a distinctive feature in the electronic spectral function when electrons couple to phonon polaritons involving an IR-active phonon mode, namely the splitting of the shake-off band into three bands. This could potentially be observed by angle-resolved photoemission spectroscopy.
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Carmele, Alexander y Stephan Reitzenstein. "Non-Markovian features in semiconductor quantum optics: quantifying the role of phonons in experiment and theory". Nanophotonics 8, n.º 5 (23 de abril de 2019): 655–83. http://dx.doi.org/10.1515/nanoph-2018-0222.
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AbstractWe discuss phonon-induced non-Markovian and Markovian features in QD-based quantum nanooptics. We cover lineshapes in linear absorption experiments, phonon-induced incoherence in the Heitler regime, and memory correlations in two-photon coherences. To qualitatively and quantitatively understand the underlying physics, we present several theoretical models that capture the non-Markovian properties of the electron–phonon interaction accurately in different regimes. Examples are the Heisenberg equation of motion approach, the polaron master equation, and Liouville propagator techniques in the independent boson limit and beyond via the path integral method. Phenomenological modeling overestimates typically the dephasing due to the finite memory kernel of phonons and we give instructive examples of phonon-mediated coherence such as phonon-dressed anticrossings in Mollow physics, robust quantum state preparation, cavity feeding, and the stabilization of the collapse and revival phenomenon in the strong coupling limit of cavity quantum electrodynamics.
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Kuroki, Yuichiro, Minoru Osada, Ariyuki Kato, Tomoichiro Okamoto y Masasuke Takata. "Exciton-Phonon Interaction in CuAlS2 Powders". Advanced Materials Research 11-12 (febrero de 2006): 175–78. http://dx.doi.org/10.4028/www.scientific.net/amr.11-12.175.
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High-resolution photoluminescence (PL) measurement was carried out for copper aluminum disulfide (CuAlS2) powder at 12 K. Several sharp PL lines were observed in the range from 3.580 to 3.320 eV. The emission peaks at photon energies from 3.566 to 3.459 eV were attributed to free-exciton (FE) and bound-excitons (BE). The several weak emissions at below 3.476 eV were clarified to be phonon replicas (PR) by Raman scattering and in the viewpoint of exciton-phonon interaction. We observed the one, two and three-phonon replicas related to E(LO, TO) and B2(LO, TO) vibrational modes in chalcopyrite structure. It was suggested that the strong interaction between excitons and optical phonons took place in obtained CuAlS2 powder.
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Rivera, Nicholas, Gilles Rosolen, John D. Joannopoulos, Ido Kaminer y Marin Soljačić. "Making two-photon processes dominate one-photon processes using mid-IR phonon polaritons". Proceedings of the National Academy of Sciences 114, n.º 52 (12 de diciembre de 2017): 13607–12. http://dx.doi.org/10.1073/pnas.1713538114.
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Phonon polaritons are guided hybrid modes of photons and optical phonons that can propagate on the surface of a polar dielectric. In this work, we show that the precise combination of confinement and bandwidth offered by phonon polaritons allows for the ability to create highly efficient sources of polariton pairs in the mid-IR/terahertz frequency ranges. Specifically, these polar dielectrics can cause emitters to preferentially decay by the emission of pairs of phonon polaritons, instead of the previously dominant single-photon emission. We show that such two-photon emission processes can occur on nanosecond time scales and can be nearly 2 orders of magnitude faster than competing single-photon transitions, as opposed to being as much as 8–10 orders of magnitude slower in free space. These results are robust to the choice of polar dielectric, allowing potentially versatile implementation in a host of materials such as hexagonal boron nitride, silicon carbide, and others. Our results suggest a design strategy for quantum light sources in the mid-IR/terahertz: ones that prefer to emit a relatively broad spectrum of photon pairs, potentially allowing for new sources of both single and multiple photons.
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Hasegawa, Takayuki. "Characteristics of Coherent Optical Phonons in a Hexagonal YMnO3 Thin Film". Applied Sciences 9, n.º 4 (18 de febrero de 2019): 704. http://dx.doi.org/10.3390/app9040704.
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This paper reviews our recent study on a coherent optical phonon in a hexagonal YMnO3 thin film together with related optical studies in hexagonal RMnO3 (R = Y, Lu, Ho) compounds. Coherent phonons have been observed in RMnO3 compounds by pump-probe spectroscopy with subpicosecond laser pulses, whereas the observation of coherent optical phonons was reported only in LuMnO3. Recently, we succeeded in the observation of the coherent optical phonon in a YMnO3 thin film. The generation process of the coherent optical phonon is assigned to a displacive mechanism, which is identical to that in LuMnO3. The coherent optical phonon is observed in the temperature range from 10 K to room temperature, while the oscillation intensity strongly decreases as the temperature increases to the Néel temperature of ~70 K from a lower temperature range. It is interesting that the temperature dependence is largely different from that in LuMnO3. We describe that the result can be qualitatively explained by the property of an isostructural transition around the Néel temperature in RMnO3 compounds. In addition, we briefly discuss ultrafast incoherent responses of excited electronic states from the viewpoint of the excitation photon energy of laser pulses.
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Murphy-Armando, F., É. D. Murray, I. Savić, M. Trigo, D. A. Reis y S. Fahy. "Electronic heat generation in semiconductors: Non-equilibrium excitation and evolution of zone-edge phonons via electron–phonon scattering in photo-excited germanium". Applied Physics Letters 122, n.º 1 (2 de enero de 2023): 012202. http://dx.doi.org/10.1063/5.0131157.
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We investigate experimentally and using first-principles theory the generation of phonons and the relaxation of carriers on picosecond timescales across the Brillouin zone of photo-excited Ge by inter-valley electron–phonon scattering. The phonons generated are typical of those generated in semiconductor devices, contributing to the accumulation of heat within the material. We simulate the time-evolution of phonon populations, based on first-principles band structure and electron–phonon and phonon–phonon matrix elements, and compare them to data from time-resolved x-ray diffuse scattering experiments, performed at the Linac Coherent Light Source x-ray free-electron laser facility, following photo-excitation by a 50 fs near-infrared optical pulse. We show that the intensity of the non-thermal x-ray diffuse scattering signal, which is observed to grow substantially near the L-point of the Brillouin zone over 3–5 ps, is due to phonons generated by scattering of carriers between the Δ and L valleys. These phonons have low group velocities, resulting in a heat bottleneck. With the inclusion of phonon decay through 3-phonon processes, the simulations also account for other non-thermal features observed in the x-ray diffuse scattering intensity, which are due to anharmonic phonon–phonon scattering of the phonons initially generated by electron–phonon scattering.
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Massoni, Eduardo y Miguel Orszag. "Phonon–photon translator". Optics Communications 179, n.º 1-6 (mayo de 2000): 315–21. http://dx.doi.org/10.1016/s0030-4018(99)00673-2.
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DOLOCAN, ANDREI, VOICU OCTAVIAN DOLOCAN y VOICU DOLOCAN. "SOME ASPECTS OF THE ELECTRON-BOSON INTERACTION AND OF THE ELECTRON-ELECTRON INTERACTION VIA BOSONS". Modern Physics Letters B 21, n.º 01 (10 de enero de 2007): 25–36. http://dx.doi.org/10.1142/s0217984907012335.
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By using a Hamiltonian of interaction between fermions via bosons1 we derive some properties of the electro-phonon and electron-photon interaction and also of the electron-electron interaction. We have obtained that in a degenerate electron gas there is an attraction between two electrons via acoustical phonons. Also, in certain conditions, there may be an attraction between two electrons via longitudinal optical phonons. Although our expressions for the polaron energy in both cases of the acoustical and longitudinal optical phonons are different from that obtained in the standard theory, their magnitudes are the same with these and they are in good agreement with experimental data. The total emission rate of an electron against a phonon system at absolute zero is directly proportional to the electron momentum. Also, an attraction between two electrons may appear via photons.
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Loktev, V. M. y M. D. Tomchenko. "On the Nature of a Narrow Roton Absorption Line in the Spectrum of a Disk-shaped SHF Resonator". Ukrainian Journal of Physics 56, n.º 1 (17 de febrero de 2022): 49. http://dx.doi.org/10.15407/ujpe56.1.49.
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We calculate the probability of the creation of a circular phonon (c-phonon) in He II by a c-photon of the resonator. It is shown that this probability has sharp maxima at frequencies, where the effective group velocity of the c-phonon is equal to zero; the density of states of c-phonons strongly grows at such frequencies. For He II, these frequencies correspond to a roton and a maxon. From theprobability of the c-roton creation, we calculate the roton line width which is found to approximately agree with the experimental one. We conclude that the roton line observed in the super-high-frequency (SHF) absorption spectrum of helium is related to the creation of c-rotons. A possible interpretation of the Stark effect observed for the roton line is also proposed.
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DUTTA, M. y M. A. STROSCIO. "ADVANCED SEMICONDUCTOR LASERS: PHONON ENGINEERING AND PHONON INTERACTIONS". International Journal of High Speed Electronics and Systems 09, n.º 04 (diciembre de 1998): 1265–77. http://dx.doi.org/10.1142/s012915649800049x.
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This account presents theoretical results on the tailoring of carrier scattering by polar-optical phonons in novel quantum-well lasers such as the tunneling injection laser and the quantum cascade laser. These scattering rates are tailored by engineering semiconductor heterostructures on a scale sufficiently small that both the phonon amplitudes and the phonon envelopes are modified by dimensional confinement. As background information on the properties of confined phonons, this account provides a brief survey of phonon confinement effects in dimensionally-confined structures.
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Kang, Nam Lyong y Sang Don Choi. "Projection-Reduction Approach to Optical Conductivities for an Electron-Phonon System and Their Diagram Representation". ISRN Condensed Matter Physics 2014 (7 de abril de 2014): 1–23. http://dx.doi.org/10.1155/2014/719120.
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Utilizing state-dependent projection operators and the Kang-Choi reduction identities, we derive the linear, first, and second-order nonlinear optical conductivities for an electron system interacting with phonons. The lineshape functions included in the conductivity tensors satisfy “the population criterion” saying that the Fermi distribution functions for electrons and Planck distribution functions for phonons should be combined in multiplicative forms. The results also contain energy denominator factors enforcing the energy conservation as well as interaction factors describing electron-phonon interaction properly. Therefore, the phonon absorption and emission processes as well as photon absorption and emission processes in all electron transition processes can be presented in an organized manner and the results can be represented in diagrams that can model the quantum dynamics of electrons in a solid.
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Zhang, Li, Hong-Jing Xie y Chuan-Yu Chen. "Electron-Phonon Interaction in a Multi-Shell Spherical Nanoheterosystem". Modern Physics Letters B 17, n.º 20n21 (10 de septiembre de 2003): 1081–94. http://dx.doi.org/10.1142/s0217984903006165.
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Under the dielectric continuum approximation, the confined longitudinal-optical (LO) phonon and interface-optical (IO) phonon modes of a multi-shell spherical nanoheterosystem are discussed. To describe the vibrations of the LO phonons, a proper eigenfunction for LO phonon modes in the core region is adopted and a legitimate eigenfunction for LO modes in the shell region is constructed. To deal with the IO phonon modes, determinant methods are employed, and the determinant deciding the frequencies of IO phonon modes are obtained. The quantized LO and IO phonons fields as well as their corresponding electron-phonon interaction Hamiltonians are also derived.
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ZOU, JIAN y BIN SHAO. "NONCLASSICAL STATES EVOLVING FROM CLASSICAL STATES IN A POLARITON SYSTEM AT LOW TEMPERATURE". International Journal of Modern Physics B 13, n.º 18 (20 de julio de 1999): 2371–85. http://dx.doi.org/10.1142/s0217979299002460.
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We show that the photon quadrature squeezing, the phonon quadrature squeezing and the polariton quadrature squeezing can exist in a model polariton system at low temperature with the photons and the phonons initially being prepared in the coherent states and the thermal states respectively and the distributions of the photons, the phonons and the polaritons can be sub-Poissonian. We also show that all these effects strongly depend on the temperature.
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Sun, J. P., H. B. Teng, G. I. Haddad, M. A. Stroscio y G. J. Iafrate. "lntersubband Relaxation in Step Quantum Well Structures". VLSI Design 8, n.º 1-4 (1 de enero de 1998): 289–93. http://dx.doi.org/10.1155/1998/17823.
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Intersubband relaxation due to electron interactions with the localized phonon modes plays an important role for population inversion in quantum well laser structures designed for intersubband lasers operating at mid-infrared to submillimeter wavelengths. In this work, intersubband relaxation rates between subbands in step quantum well structures are evaluated numerically using Fermi's golden rule, in which the localized phonon modes including the asymmetric interface modes, symmetric interface modes, and confined phonon modes and the electron – phonon interaction Hamiltonians are derived based on the macroscopic dielectric continuum model, whereas the electron wave functions are obtained by solving the Schrödinger equation for the heterostructures under investigation. The sum rule for the relationship between the form factors of the various localized phonon modes and the bulk phonon modes is examined and verified for these structures. The intersubband relaxation rates due to electron scattering by the asymmetric interface phonons, symmetric interface phonons, and confined phonons are calculated and compared with the relaxation rates calculated using the bulk phonon modes and the Fröhlich interaction Hamiltonian for step quantum well structures with subband separations of 36 meV and 50meV, corresponding to the bulk longitudinal optical phonon energy and interface phonon energy, respectively. Our results show that for preferential electron relaxation in intersubband laser structures, the effects of the localized phonon modes, especially the interface phonon modes, must be included for optimal design of these structures.
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Matveenko, S. I. y S. Brazovskii. "Theory of pseudogaps in charge density waves in application to photo electron spectroscopy". Journal de Physique IV 12, n.º 9 (noviembre de 2002): 73. http://dx.doi.org/10.1051/jp4:20020358.
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For a one-dimensional electron-phonon system we consider the photon absorption involving electronic excitations within the pseudogap energy range. Within the adiabatic approximation for the electron - phonon interactions these processes are described by ronlinear configurations of an instanton type. We calculate the subgap absorption as it can be observed by means of photo electron or tunneling spectroscopies. In details we consider systems with gapless modes: 1D semiconductors with acoustic phonons and incommensurate charge density waves. We found that below the free particle edge the pseudogap starts with the exponential decrease of transition rates changing to a power law deeply within the pseudogap, near the absolute edge.
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Kiselev A I, Shevchenko V G. y Konyukova A.V. "Influence of photon-phonon interaction on the optical properties of aluminum powder". Optics and Spectroscopy 130, n.º 10 (2022): 1223. http://dx.doi.org/10.21883/eos.2022.10.54857.3324-22.
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By comparing the simulated and experimental optical conductivity, the electronic structure of the aluminum film and powder at room temperature was studied. The main attention is paid to the region of the optical conductivity spectrum at absorbed photon energies above 1.3 eV. It is assumed that in this section the form of the optical conductivity spectrum of aluminum powder is largely determined by the processes of heat release during photon-phonon interaction. From a comparison of the electronic characteristics of the spectra of the film and aluminum powder, the lower limits of the forbidden band of optical phonons of the metal-oxide interface are presumably established. Keywords: phonons, ellipsometry, optical properties of the film, electronic characteristics of optical transitions
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Zhao, Feng Qi y Xiao Mei Dai. "Influence of Pressure on Polaron Energy in a Wurtzite GaN/AlxGa1-xN Quantum Well". Solid State Phenomena 288 (marzo de 2019): 17–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.288.17.
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The influence of hydrostatic pressure on the polaron energy level in wurtzite GaN/AlxGa1-xN quantum well is studied by a Lee-Low-Pines variational method, and the numerical results of the ground state energy, transition energy and contributions of different phonons to polaron energy (polaron effects) are given as functions of pressurepand compositionx. The results show that the ground state energy and transition energy in the wurtzite GaN/AlxGa1-xN quantum well decrease with the increase of the hydrostatic pressurep, and increase with the increase of the compositionx. The contributions of different phonons to polaron energy with pressurepand compositionxare obviously different. With the increase of hydrostatic pressure, the contribution of half-space phonon, confined phonon and the total contribution of phonons of all branches increases obviously, while the contribution of interface phonon slowly increases. During the increase of the composition, the contribution of interface phonon decreases and the contribution of half-space phonon increases slowly, while the contribution of confined phonon and the total contribution of phonons increases significantly. In general, the electron-optical phonon interaction play an important role in electronic states of GaN/AlxGa1-xN quantum wells and can not be neglected.
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Fan, Huanrong, Faizan Raza, Irfan Ahmed, Muhammad Imran, Faisal Nadeem, Changbiao Li, Peng Li y Yanpeng Zhang. "Photon–Phonon Atomic Coherence Interaction of Nonlinear Signals in Various Phase Transitions Eu3+: BiPO4". Nanomaterials 12, n.º 23 (4 de diciembre de 2022): 4304. http://dx.doi.org/10.3390/nano12234304.
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We report photon–phonon atomic coherence (cascade- and nested-dressing) interaction from the various phase transitions of Eu3+: BiPO4 crystal. Such atomic coherence spectral interaction evolves from out-of-phase fluorescence to in-phase spontaneous four-wave mixing (SFWM) by changing the time gate. The dressing dip switch and three dressing dips of SFWM result from the strong photon–phonon destructive cross- and self-interaction for the hexagonal phase, respectively. More phonon dressing results in the destructive interaction, while less phonon dressing results in the constructive interaction of the atomic coherences. The experimental measurements of the photon–phonon interaction agree with the theoretical simulations. Based on our results, we proposed a model for an optical transistor (as an amplifier and switch).
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Ibragimov, Guseyn B. y Raida Z. Ibayeva. "Intraband Absorption of Electromagnetic Radiation by Electrons with Optical Phonon Participation in Quantum Dot Superlattices". Radioelectronics. Nanosystems. Information Technologies. 16, n.º 2 (25 de abril de 2024): 249–54. http://dx.doi.org/10.17725/j.rensit.2024.16.249.
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Physics Institute of Azerbaijan National Academy of Sciences In this paper, we investigate the absorption of electromagnetic radiation by a free electron gas interacting with lattice vibrations in a quantum dot superlattice. It is assumed that the electron gas in the quantum dot superlattice is limited by the anisotropic parabolic potential. The absorption of light by free carriers with the participation of phonons is calculated in the second order of the perturbation theory. When calculating the absorption coefficient, the matrix elements of the electron-photon and electron-phonon interactions (with polar and nonpolar optical phonons) are used. We can expect three possible transitions in the absorption coefficient for electron-polar phonon scattering: (1) a transition due to the size subband levels for only the x direction, (2) a transition due to the size subband levels for only the y direction and (3) a transition due to the size subband levels for both the x direction and the y direction. For electron-nonpolar phonon scattering we can expect оnly one possible transitions in the, the absorption coefficient: a transition due to the size subband levels for both the x direction and the y direction.
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Singh, Anu, Hempal Singh, Vinod Ashokan y B. D. Indu. "Electrons and Phonons in High Temperature Superconductors". Journal of Materials 2013 (14 de febrero de 2013): 1–4. http://dx.doi.org/10.1155/2013/605929.
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The defect-induced anharmonic phonon-electron problem in high-temperature superconductors has been investigated with the help of double time thermodynamic electron and phonon Green’s function theory using a comprehensive Hamiltonian which includes the contribution due to unperturbed electrons and phonons, anharmonic phonons, impurities, and interactions of electrons and phonons. This formulation enables one to resolve the problem of electronic heat transport and equilibrium phenomenon in high-temperature superconductors in an amicable way. The problem of electronic heat capacity and electron-phonon problem has been taken up with special reference to the anharmonicity, defect concentration electron-phonon coupling, and temperature dependence.
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Shi, Jun-jie, B. C. Sanders y Shao-hua Pan. "Coherent and Phonon-assisted Tunnelling in Asymmetric Double Barrier Resonant Tunnelling Structures". Australian Journal of Physics 53, n.º 1 (2000): 35. http://dx.doi.org/10.1071/ph99037.
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We present a theory for calculating the phonon-assisted tunnelling current in asymmetric double barrier resonant tunnelling structures (DBRTS), in which all of the phonon modes including the interface modes and the confined bulk-like LO phonons and the conduction band nonparabolicity are considered. An important physical picture about coherent and phonon-assisted tunnelling is given. The coherent tunnelling current can be directly determined by both the width of the resonant level and the peak value of the transmission coecient at the resonant level. The phonon-assisted tunnelling current mainly comes from electron interaction with higher frequency interface phonons (especially the interface phonons localised at either interface of the left barrier). Phonon-assisted tunnelling makes a significant contribution to the valley current. The subband nonparabolicity strongly influences on electron?phonon scattering and current-to-voltage characteristics. A specially designed asymmetric DBRTS may have an improved performance over the symmetric DBRTS.
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Kuleyev I. G. y Kuleyev I. I. "The Effect of phonon focusing on the mutual drag of electrons and phonons and the electrical resistance of potassium". Physics of the Solid State 64, n.º 8 (2022): 901. http://dx.doi.org/10.21883/pss.2022.08.54601.324.
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The effect influence of elastic energy anisotropy on the mutual drag of electrons and phonons and the electrical resistance of potassium crystals at low temperatures have investigated. We have analyzed the momentum exchange between the electron and three phonon flows corresponding to three branches of the vibrational spectrum in the hydrodynamic approximation. The actual mechanisms of phonon momentum relaxation have taken into account: scattering at sample boundaries, dislocations, and in the processes of phonon-phonon transfer. It have shown that in the limiting case of strong mutual drag of electrons and phonons, the electrical resistance will be much lower than that given by the Bloch--Gruneisen theory, and the phonon and electron drift velocities are close and they are determined by the total phonon relaxation rate in resistive scattering processes. In the opposite case, when resistive scattering processes dominate for phonons and the phonon system remains in equilibrium, then the electrical resistance follows the Bloch--Gruneisen theory. In this case, the drift velocities of all modes are different and much less than the electron drift velocity. Keywords: electrical resistance, elastic anisotropy, electron-phonon relaxation.
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Кулеев, И. Г. y И. И. Кулеев. "Влияние фокусировки на взаимное увлечение электронов и фононов и электросопротивление кристаллов калия". Физика твердого тела 64, n.º 8 (2022): 899. http://dx.doi.org/10.21883/ftt.2022.08.52680.324.
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The effect influence of elastic energy anisotropy on the mutual drag of electrons and phonons and the electrical resistance of potassium crystals at low temperatures have investigated. We have analyzed the momentum exchange between the electron and three phonon flows corresponding to three branches of the vibrational spectrum in the hydrodynamic approximation. The actual mechanisms of phonon momentum relaxation have taken into account: scattering at sample boundaries, dislocations, and in the processes of phonon-phonon transfer. It have shown that in the limiting case of strong mutual drag of electrons and phonons, the electrical resistance will be much lower than that given by the Bloch–Grüneisen theory, and the phonon and electron drift velocities are close and they are determined by the total phonon relaxation rate in resistive scattering processes. In the opposite case, when resistive scattering processes dominate for phonons and the phonon system remains in equilibrium, then the electrical resistance follows the Bloch–Grüneisen theory. In this case, the drift velocities of all modes are different and much less than the electron drift velocity.
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Bannov, N. A., V. V. Mitin y F. T. Vasko. "Modelling of Hot Acoustic Phonon Propagation in Two Dimensional Layers". VLSI Design 6, n.º 1-4 (1 de enero de 1998): 197–200. http://dx.doi.org/10.1155/1998/79658.
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The transport of confined acoustic phonons in a flee-standing quantum well has been studied by solving the quantum kinetic equation for phonons. The phonon decay rate has been numerically calculated for GaAs flee-standing quantum well. Phonon interaction with electrons through the deformation potential makes the major contribution to the acoustic phonon decay.
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Manley, M. E., K. Hong, P. Yin, S. Chi, Y. Cai, C. Hua, L. L. Daemen et al. "Giant isotope effect on phonon dispersion and thermal conductivity in methylammonium lead iodide". Science Advances 6, n.º 31 (julio de 2020): eaaz1842. http://dx.doi.org/10.1126/sciadv.aaz1842.
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Lead halide perovskites are strong candidates for high-performance low-cost photovoltaics, light emission, and detection applications. A hot-phonon bottleneck effect significantly extends the cooling time of hot charge carriers, which thermalize through carrier–optic phonon scattering, followed by optic phonon decay to acoustic phonons and finally thermal conduction. To understand these processes, we adjust the lattice dynamics independently of electronics by changing isotopes. We show that doubling the mass of hydrogen in methylammonium lead iodide by replacing protons with deuterons causes a large 20 to 50% softening of the longitudinal acoustic phonons near zone boundaries, reduces thermal conductivity by ~50%, and slows carrier relaxation kinetics. Phonon softening is attributed to anticrossing with the slowed libration modes of the deuterated molecules and the reduced thermal conductivity to lowered phonon velocities. Our results reveal how tuning the organic molecule dynamics enables control of phonons important to thermal conductivity and the hot-phonon bottleneck.
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PHUONG, LE THI THU y TRAN CONG PHONG. "RATE OF CONFINED PHONON EXCITATION IN RECTANGULAR QUANTUM WIRES". International Journal of Computational Materials Science and Engineering 01, n.º 01 (marzo de 2012): 1250002. http://dx.doi.org/10.1142/s2047684112500029.
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We present a theory of phonon generation via the Cerenkov effect in rectangular quantum wires (RQWs) based on the quantum kinetic equation for phonon population operator. Analytical expressions for the rate of change of the phonon population and conditions for phonon generation are obtained. Both electrons and phonons are confined. Numerical results for a specific RQW show that the amplitude of the laser field must satisfy additional conditions that are different in comparison with those of the generation of bulk phonons.
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Dekorsy, Thomas, Gyu Cheon Cho y Heinrich Kurz. "Coherent Phonons in Semiconductors and Semiconductor Heterostructures". Journal of Nonlinear Optical Physics & Materials 07, n.º 02 (junio de 1998): 201–13. http://dx.doi.org/10.1142/s021886359800017x.
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The impulsive excitation and phase-sensitive detection of coherent phonons enable the study of dynamical properties of the lattice. In pump-probe experiments with femtosecond time resolution the amplitude and phase of the coherent lattice motion can be detected with high sensitivity. Especially in semiconductors and semiconductor heterostructures, where a coherent phonon mode and free carriers are exited at the same time, important information about the carrier-phonon system far away from equilibrium is obtained. In bulk GaAs coherent plasmon-phonon modes can be traced via the associated macroscopic field. In GaAs-AlGaAs based heterostructures coupled phonon-intersubband plasmons, coupled Bloch-phonon oscillations, and coherent acoustic phonons are observed.
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TAKESHIMA, MASUMI, K. MIZUNO y ATSUO H. MATSUI. "PHONON SCATTERING OF FRENKEL EXCITONS IN MOLECULAR MICROCRYSTALLITES EMBEDDED IN A MATRIX". International Journal of Modern Physics B 15, n.º 28n30 (10 de diciembre de 2001): 3973–76. http://dx.doi.org/10.1142/s021797920100913x.
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A matrix effect on the exciton-phonon coupling in microcrystallites embedded in a matrix is investigated theoretically. It is shown that a parameter σ defined as the square of the ratio of the phonon bandwidth of a matrix material to that of a microcrystallite material is a crucial one, affecting the exciton-phonon scattering. Phonons flow in the microcrystallite or out of it for either of σ > 1 or σ < 1, respectively; the probability for finding phonons in the microcrystallite increases with increasing σ. Thus the strength of the exciton-phonon coupling in the microcrystallite is influenced by phonons in the matrix. The flowing-in of phonons, which have energies higher than the maximum energy of phonons in the microcrystallite material, is of special importance and results in the broadening of the lines constituting an optical absorption spectrum.
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Thu Huong, Nguyen, Tang Thi Dien, Nguyen Quang Bau, Tran Khuong Duy, Nguyen Dinh Nam y Dao Thanh Hue. "Photostimulated Nernst effect in two-dimensional compositional semiconductor superlattices under the influence of confined phonons". Journal of Physics: Conference Series 2744, n.º 1 (1 de abril de 2024): 012004. http://dx.doi.org/10.1088/1742-6596/2744/1/012004.
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Abstract The photostimulated Nernst effect in compositional semiconductor superlattices under the influence of a confined acoustic phonon is studied by using the quantum kinetic equation. The case of the confined electron-confined acoustic phonon scattering process is examined in detail. The obtained analytical results reveal that the Nernst coefficient (NC) depends on the external field such as magnetic field B, the frequency Ω, and the amplitude E 0 of the electromagnetic wave in a complicated way but also like a function of the temperature of the system and the period of the superlattice. It also depends on the quantum number m-describing the confined acoustic phonon. The theoretical results are depicted and discussed for GaAs/AlxGa 1 − xAs compositional semiconductors superlattices. The results indicate that the Shubnikov-De hass oscillations have appeared. The confined phonons make the magnitude of the Nernst coefficient higher and more obvious than the case of a bulk phonon. In addition, the magneto-photon resonance condition is also proved. Besides, the Nernst coefficient decreases significantly as the temperature increases. The oscillations Nernst coefficient in a magnetic field are consistent with the previous experimental.
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Chen, J. y Y. Liu. "Effect of out-of-plane acoustic phonons on the thermal transport properties of graphene". Condensed Matter Physics 26, n.º 4 (2023): 43603. http://dx.doi.org/10.5488/cmp.26.43603.
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The lattice thermal conductivity of graphene is evaluated using a microscopic model that takes into account the lattice's discrete nature and the phonon dispersion relation within the Brillouin zone. The Boltzmann transport equation is solved iteratively within the framework of three-phonon interactions without taking into account the four-phonon scattering process. The Umklapp and normal collisions are treated rigorously, thereby avoiding relaxation-time and long-wavelength approximations. The mechanisms of the failures of these approximations in predicting the thermal transport properties are discussed. Evaluation of the thermal conductivity is performed at different temperatures and frequencies and in different crystallite sizes. Reasonably good agreement with the experimental data is obtained. The calculation reveals a critical role of out-of-plane acoustic phonons in determining the thermal conductivity. The out-of-plane acoustic phonons contribute greatly and the longitudinal and transverse acoustic phonons make small contributions over a wide range of temperatures and frequencies. The out-of-plane acoustic phonons dominate the thermal conductivity due to their high density of states and restrictions governing the anharmonic phonon scattering. The selection rule severely restricts the phase space for out-of-plane phonon scattering due to reflection symmetry. The optical phonon contribution cannot be neglected at higher temperatures. Both Umklapp and normal processes must be taken into account in order to predict the phonon transport properties accurately.
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Ren, Weijun, Jie Chen y Gang Zhang. "Phonon physics in twisted two-dimensional materials". Applied Physics Letters 121, n.º 14 (3 de octubre de 2022): 140501. http://dx.doi.org/10.1063/5.0106676.
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As one of the most effective manipulation means to control the physical properties of two-dimensional van der Waals stacking materials, the twisted angle periodically regulates the interlayer interaction potential by generating moiré patterns. The decrease in Brillouin zone size and the change of high symmetry direction caused by the interlayer twisted angle lead to the emergence of the hybrid folded phonons—moiré phonons, which have noticeable impacts on phonon properties. This paper reviews the recent developments and discoveries on phonon properties in twisted two-dimensional stacking homogeneous and heterogeneous systems and focuses on the impacts of the interlayer twisted angle on phonon dispersion, such as interlayer coupling phonon modes and moiré phonons. Meanwhile, we introduced the recent research on the influence of the interlayer twisted angle on phonon transport behavior along the in-plane and out-of-plane directions. In addition, the theoretical and experimental open questions and challenges faced in the phonon characteristics of twisted two-dimensional materials are discussed, and some possible solutions are put forward.
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Liu, Xinyu, Quanjie Wang, Renzong Wang, Sheng Wang y Xiangjun Liu. "Impact of interfacial compositional diffusion on interfacial phonon scattering and transmission in GaN/AlN heterostructure". Journal of Applied Physics 133, n.º 9 (7 de marzo de 2023): 095101. http://dx.doi.org/10.1063/5.0134903.
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Compositional diffusion at interfaces often occurs during the synthesis of heterostructures, which poses a significant challenge to the reliability and performance of heterostructure-based electronic devices. In this study, the effect of interfacial compositional diffusion on the interfacial phonon transport in GaN/AlN heterostructures has been explored using molecular dynamics and phonon dynamics simulations. It is found the compositional diffusion results in a remarkable reduction in the interfacial thermal conductance (ITC) of the heterostructures, which can be modulated by tuning the compositional diffusion thickness. Phonon wave packet simulations further revealed that the energy transmission coefficient across the interface is strongly phonon frequency-dependent and interfacial morphology-dependent, which is consistent well with the calculated ITC of the structures. The phonon mode conversion and phonon localization are observed at the region of interfaces. Furthermore, it is found that the longitudinal acoustic phonons are more sensitive to the compositional diffusion interface than transverse-acoustic phonons do. However, it is interesting to find that the energy transmission coefficients of transverse-acoustic phonons with a high frequency (above 3.6 THz) across the compositional interface are abnormally higher than those across the sharp interface due to the stronger phonon mode conversion in the compositional diffusion region, which provides additional pathways for energy transmission. Our findings provide a deeper insight into the interfacial phonon scattering and transmission under the coupling effect of interfacial morphology and compositional diffusion.
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Yin, Tai-Shuang, Guang-Ri Jin y Aixi Chen. "Enhanced Phonon Antibunching in a Circuit Quantum Acoustodynamical System Containing Two Surface Acoustic Wave Resonators". Micromachines 13, n.º 4 (9 de abril de 2022): 591. http://dx.doi.org/10.3390/mi13040591.
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We propose a scheme to implement the phonon antibunching and phonon blockade in a circuit quantum acoustodynamical system containing two surface acoustic wave (SAW) resonators coupled to a superconducting qubit. In the cases of driving only one SAW resonator and two SAW resonators, we investigate the phonon statistics by numerically calculating the second-order correlation function. It is found that, when only one SAW cavity is resonantly driven, the phonon antibunching effect can be achieved even when the qubit–phonon coupling strength is smaller than the decay rates of acoustic cavities. This result physically originates from the quantum interference between super-Poissonian statistics and Poissonian statistics of phonons. In particular, when the two SAW resonators are simultaneously driven under the mechanical resonant condition, the phonon antibunching effect can be significantly enhanced, which ultimately allows for the generation of a phonon blockade. Moreover, the obtained phonon blockade can be optimized by regulating the intensity ratio of the two SAW driving fields. In addition, we also discuss in detail the effect of system parameters on the phonon statistics. Our work provides an alternative way for manipulating and controlling the nonclassical effects of SAW phonons. It may inspire the engineering of new SAW-based phonon devices and extend their applications in quantum information processing.
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Luckyanova, M. N., J. Mendoza, H. Lu, B. Song, S. Huang, J. Zhou, M. Li et al. "Phonon localization in heat conduction". Science Advances 4, n.º 12 (diciembre de 2018): eaat9460. http://dx.doi.org/10.1126/sciadv.aat9460.
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Nondiffusive phonon thermal transport, extensively observed in nanostructures, has largely been attributed to classical size effects, ignoring the wave nature of phonons. We report localization behavior in phonon heat conduction due to multiple scattering and interference events of broadband phonons, by measuring the thermal conductivities of GaAs/AlAs superlattices with ErAs nanodots randomly distributed at the interfaces. With an increasing number of superlattice periods, the measured thermal conductivities near room temperature increased and eventually saturated, indicating a transition from ballistic to diffusive transport. In contrast, at cryogenic temperatures the thermal conductivities first increased but then decreased, signaling phonon wave localization, as supported by atomistic Greenșs function simulations. The discovery of phonon localization suggests a new path forward for engineering phonon thermal transport.
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Jin, Jae Sik y Joon Sik Lee. "Electron–Phonon Interaction Model and Prediction of Thermal Energy Transport in SOI Transistor". Journal of Nanoscience and Nanotechnology 7, n.º 11 (1 de noviembre de 2007): 4094–100. http://dx.doi.org/10.1166/jnn.2007.010.
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An electron–phonon interaction model is proposed and applied to thermal transport in semiconductors at micro/nanoscales. The high electron energy induced by the electric field in a transistor is transferred to the phonon system through electron–phonon interaction in the high field region of the transistor. Due to this fact, a hot spot occurs, which is much smaller than the phonon mean free path in the Si-layer. The full phonon dispersion model based on the Boltzmann transport equation (BTE) with the relaxation time approximation is applied for the interactions among different phonon branches and different phonon frequencies. The Joule heating by the electron–phonon scattering is modeled through the intervalley and intravalley processes for silicon by introducing average electron energy. The simulation results are compared with those obtained by the full phonon dispersion model which treats the electron–phonon scattering as a volumetric heat source. The comparison shows that the peak temperature in the hot spot region is considerably higher and more localized than the previous results. The thermal characteristics of each phonon mode are useful to explain the above phenomena. The optical mode phonons of negligible group velocity obtain the highest energy density from electrons, and resides in the hot spot region without any contribution to heat transport, which results in a higher temperature in that region. Since the acoustic phonons with low group velocity show the higher energy density after electron–phonon scattering, they induce more localized heating near the hot spot region. The ballistic features are strongly observed when phonon–phonon scattering rates are lower than 4 × 1010 s−1.
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Jin, Jae Sik y Joon Sik Lee. "Electron–Phonon Interaction Model and Prediction of Thermal Energy Transport in SOI Transistor". Journal of Nanoscience and Nanotechnology 7, n.º 11 (1 de noviembre de 2007): 4094–100. http://dx.doi.org/10.1166/jnn.2007.18084.
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An electron–phonon interaction model is proposed and applied to thermal transport in semiconductors at micro/nanoscales. The high electron energy induced by the electric field in a transistor is transferred to the phonon system through electron–phonon interaction in the high field region of the transistor. Due to this fact, a hot spot occurs, which is much smaller than the phonon mean free path in the Si-layer. The full phonon dispersion model based on the Boltzmann transport equation (BTE) with the relaxation time approximation is applied for the interactions among different phonon branches and different phonon frequencies. The Joule heating by the electron–phonon scattering is modeled through the intervalley and intravalley processes for silicon by introducing average electron energy. The simulation results are compared with those obtained by the full phonon dispersion model which treats the electron–phonon scattering as a volumetric heat source. The comparison shows that the peak temperature in the hot spot region is considerably higher and more localized than the previous results. The thermal characteristics of each phonon mode are useful to explain the above phenomena. The optical mode phonons of negligible group velocity obtain the highest energy density from electrons, and resides in the hot spot region without any contribution to heat transport, which results in a higher temperature in that region. Since the acoustic phonons with low group velocity show the higher energy density after electron–phonon scattering, they induce more localized heating near the hot spot region. The ballistic features are strongly observed when phonon–phonon scattering rates are lower than 4 × 1010 s−1.
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Timsina, Sanker, Taha Hammadia, Sahar Gholami Milani, Filomeno S. de Aguiar Júnior, Alexandre Brolo y Rogério de Sousa. "Resonant squeezed light from photonic Cooper pairs". Physical Review Research 6, n.º 3 (15 de julio de 2024). http://dx.doi.org/10.1103/physrevresearch.6.033067.
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Raman scattering of photons into phonons gives rise to entangled photon pairs when the phonon emitted in a Stokes process is coherently absorbed in antiStokes scattering, forming the photonic analog of Cooper pairs. We present a nonperturbative theory for the time evolution of photonic Cooper pairs that treats interacting photons and phonons as a hybrid excitation, the Ramaniton. As the Ramaniton propagates in a waveguide it displays quantum oscillations between photon and phonon occupation, leading to resonant squeezed Stokes-antiStokes light when the phonon occupation becomes equal to zero without recurring back to the photon vacuum. This phenomenon is predicted to generate up to 28 dB of squeezed light even in standard silicon on insulator waveguides. Published by the American Physical Society 2024
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Abo, Shilan, Grzegorz Chimczak, Anna Kowalewska-Kudłaszyk, Jan Peřina, Ravindra Chhajlany y Adam Miranowicz. "Hybrid photon–phonon blockade". Scientific Reports 12, n.º 1 (21 de octubre de 2022). http://dx.doi.org/10.1038/s41598-022-21267-4.
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AbstractWe describe a novel type of blockade in a hybrid mode generated by linear coupling of photonic and phononic modes. We refer to this effect as hybrid photon–phonon blockade and show how it can be generated and detected in a driven nonlinear optomechanical superconducting system. Thus, we study boson-number correlations in the photon, phonon, and hybrid modes in linearly coupled microwave and mechanical resonators with a superconducting qubit inserted in one of them. We find such system parameters for which we observe eight types of different combinations of either blockade or tunnelling effects (defined via the sub- and super-Poissonian statistics, respectively) for photons, phonons, and hybrid bosons. In particular, we find that the hybrid photon–phonon blockade can be generated by mixing the photonic and phononic modes which do not exhibit blockade.
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Fu, Yu, Fei Liang, Cheng He, Haohai Yu, Huaijin Zhang y Yan-Feng Chen. "Photon-phonon collaboratively pumped laser". Nature Communications 14, n.º 1 (7 de diciembre de 2023). http://dx.doi.org/10.1038/s41467-023-43959-9.
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AbstractIn 1917, Einstein considered stimulated photon emission of electron radiation, offering the theoretical foundation for laser, technically achieved in 1960. However, thermal phonons along with heat creation of non-radiative transition, are ineffective, even playing a detrimental role in lasing efficiency. Here, we realize a photon-phonon collaboratively pumped laser enhanced by heat in a counterintuitive way. We observe a laser transition from phonon-free 1064 nm lasing to phonon-pumped 1176 nm lasing in Nd:YVO4 crystal, associated with the phonon-pumped population inversion under high temperatures. Moreover, an additional temperature threshold (Tth) appears besides the photon-pump power threshold (Pth), and a two-dimensional lasing phase diagram is verified with a general relation ruled by Pth = C/Tth (constant C upon loss for a given crystal), similar to Curie’s Law. Our strategy will promote the study of laser physics via dimension extension, searching for highly efficient and low-threshold laser devices via this temperature degree of freedom.
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Kuznetsov, Alexander Sergeevich, Klaus Biermann, Andres Alejandro Reynoso, Alejandro Fainstein y Paulo Ventura Santos. "Microcavity phonoritons – a coherent optical-to-microwave interface". Nature Communications 14, n.º 1 (18 de septiembre de 2023). http://dx.doi.org/10.1038/s41467-023-40894-7.
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AbstractOptomechanical systems provide a pathway for the bidirectional optical-to-microwave interconversion in (quantum) networks. These systems can be implemented using hybrid platforms, which efficiently couple optical photons and microwaves via intermediate agents, e.g. phonons. Semiconductor exciton-polariton microcavities operating in the strong light-matter coupling regime offer enhanced coupling of near-infrared photons to GHz phonons via excitons. Furthermore, a new coherent phonon-exciton-photon quasiparticle termed phonoriton, has been theoretically predicted to emerge in microcavities, but so far has eluded observation. Here, we experimentally demonstrate phonoritons, when two exciton-polariton condensates confined in a μm-sized trap within a phonon-photon microcavity are strongly coupled to a confined phonon which is resonant with the energy separation between the condensates. We realize control of phonoritons by piezoelectrically generated phonons and resonant photons. Our findings are corroborated by quantitative models. Thus, we establish zero-dimensional phonoritons as a coherent microwave-to-optical interface.
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Wang, Tie, Wei Zhang, Ji Cao y Hong-Fu Wang. "Exceptional-point-engineered phonon laser in a cavity magnomechanical system". New Journal of Physics, 15 de agosto de 2023. http://dx.doi.org/10.1088/1367-2630/acf068.
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Abstract We propose a scheme to engineer phonon laser in a non-Hermitian cavity magnomechanical system with dissipative magnon-photon coupling. The exceptional point (the analog of the $\mathcal{PT}$-symmetric regime), emerging in the system and changing the properties of photons, magnons, and phonons, can be observed with a tunable dissipative magnon-photon coupling caused by the cavity Lenz's law. At the exceptional point, we find that a strong nonlinear relation appears between the mechanical amplification factor and the detuning parameter, which results in a dramatic enhancement of magnetostrictive force and mechanical gain, and leading to the highly efficient phonon laser and the ultralow threshold power. Furthermore, exceptional point induced by dissipative coupling is flexible and tunable compared to the $\mathcal{PT}$-symmetric regime, and the ultralow threshold power phonon laser is immune to the loss rates of the photon and magnon modes. Our scheme provides a theoretical basis for phonon laser in non-Hermitian systems and presents potential applications ranging from preparing coherent phonon sources to operating on-chip functional acoustic devices.
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Chafatinos, D. L., A. S. Kuznetsov, S. Anguiano, A. E. Bruchhausen, A. A. Reynoso, K. Biermann, P. V. Santos y A. Fainstein. "Polariton-driven phonon laser". Nature Communications 11, n.º 1 (11 de septiembre de 2020). http://dx.doi.org/10.1038/s41467-020-18358-z.
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Abstract Efficient generation of phonons is an important ingredient for a prospective electrically-driven phonon laser. Hybrid quantum systems combining cavity quantum electrodynamics and optomechanics constitute a novel platform with potential for operation at the extremely high frequency range (30–300 GHz). We report on laser-like phonon emission in a hybrid system that optomechanically couples polariton Bose-Einstein condensates (BECs) with phonons in a semiconductor microcavity. The studied system comprises GaAs/AlAs quantum wells coupled to cavity-confined optical and vibrational modes. The non-resonant continuous wave laser excitation of a polariton BEC in an individual trap of a trap array, induces coherent mechanical self-oscillation, leading to the formation of spectral sidebands displaced by harmonics of the fundamental 20 GHz mode vibration frequency. This phonon “lasing” enhances the phonon occupation five orders of magnitude above the thermal value when tunable neighbor traps are red-shifted with respect to the pumped trap BEC emission at even harmonics of the vibration mode. These experiments, supported by a theoretical model, constitute the first demonstration of coherent cavity optomechanical phenomena with exciton polaritons, paving the way for new hybrid designs for quantum technologies, phonon lasers, and phonon-photon bidirectional translators.
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Melvin, Daniel, Fulu Zheng, Kewei Sun, Zhengjie Tan y Yang Zhao. "Photon‐Assisted Landau Zener Transitions in a Tunable Driven Rabi Dimer Coupled to a Micromechanical Resonator". Advanced Quantum Technologies, 27 de septiembre de 2023. http://dx.doi.org/10.1002/qute.202300232.
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AbstractEmploying the multiple Davydov D2 Ansätze with the time‐dependent variational principle, photon‐assisted Landau–Zener (LZ) transitions and qubit manipulation in a hybrid quantum electrodynamics device have been investigated. Modeled as a Rabi dimer, the device comprises of two interacting transmission‐line resonators, each coupled to a qubit. The qubits, driven by independent harmonic fields, are further modulated by a micromechanical resonator mimicked by a phonon mode. The impacts of two independent driving fields on the qubit dynamics are carefully examined. The energy diagram of the system and the photon number mobilization on the resonators are analyzed to explain the behavior of the LZ transitions and qubit dynamics while taking into account the influence of the single phonon mode. Results show that low phonon frequencies can alter the qubit dynamics, particularly in the absence of the driving fields, and a strong phonon coupling strength can significantly perturb the qubit dynamics, thanks to a high influx of phonon energy. Notably, only the photon frequency affects the oscillation frequency of qubit polarization. This study unveils the imperative roles that photons and phonons play in the Rabi dimer model.
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Yazdani, Nuri, Maximilian Jansen, Deniz Bozyigit, Weyde M. M. Lin, Sebastian Volk, Olesya Yarema, Maksym Yarema, Fanni Juranyi, Sebastian D. Huber y Vanessa Wood. "Nanocrystal superlattices as phonon-engineered solids and acoustic metamaterials". Nature Communications 10, n.º 1 (17 de septiembre de 2019). http://dx.doi.org/10.1038/s41467-019-12305-3.
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Abstract Phonon engineering of solids enables the creation of materials with tailored heat-transfer properties, controlled elastic and acoustic vibration propagation, and custom phonon–electron and phonon–photon interactions. These can be leveraged for energy transport, harvesting, or isolation applications and in the creation of novel phonon-based devices, including photoacoustic systems and phonon-communication networks. Here we introduce nanocrystal superlattices as a platform for phonon engineering. Using a combination of inelastic neutron scattering and modeling, we characterize superlattice-phonons in assemblies of colloidal nanocrystals and demonstrate that they can be systematically engineered by tailoring the constituent nanocrystals, their surfaces, and the topology of superlattice. This highlights that phonon engineering can be effectively carried out within nanocrystal-based devices to enhance functionality, and that solution processed nanocrystal assemblies hold promise not only as engineered electronic and optical materials, but also as functional metamaterials with phonon energy and length scales that are unreachable by traditional architectures.
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Barra-Burillo, María, Unai Muniain, Sara Catalano, Marta Autore, Fèlix Casanova, Luis E. Hueso, Javier Aizpurua, Ruben Esteban y Rainer Hillenbrand. "Microcavity phonon polaritons from the weak to the ultrastrong phonon–photon coupling regime". Nature Communications 12, n.º 1 (27 de octubre de 2021). http://dx.doi.org/10.1038/s41467-021-26060-x.
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AbstractStrong coupling between molecular vibrations and microcavity modes has been demonstrated to modify physical and chemical properties of the molecular material. Here, we study the less explored coupling between lattice vibrations (phonons) and microcavity modes. Embedding thin layers of hexagonal boron nitride (hBN) into classical microcavities, we demonstrate the evolution from weak to ultrastrong phonon-photon coupling when the hBN thickness is increased from a few nanometers to a fully filled cavity. Remarkably, strong coupling is achieved for hBN layers as thin as 10 nm. Further, the ultrastrong coupling in fully filled cavities yields a polariton dispersion matching that of phonon polaritons in bulk hBN, highlighting that the maximum light-matter coupling in microcavities is limited to the coupling strength between photons and the bulk material. Tunable cavity phonon polaritons could become a versatile platform for studying how the coupling strength between photons and phonons may modify the properties of polar crystals.
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Ding, Ming-Song, Li Zheng y Chong Li. "Phonon laser in a cavity magnomechanical system". Scientific Reports 9, n.º 1 (31 de octubre de 2019). http://dx.doi.org/10.1038/s41598-019-52050-7.
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Abstract Using phonons to simulate an optical two-level laser action has been the focus of research. We theoretically study phonon laser in a cavity magnomechanical system, which consist of a microwave cavity, a sphere of magnetic material and a uniform external bias magnetic field. This system can realize the phonon-magnon coupling and the cavity photon-magnon coupling via magnetostrictive interaction and magnetic dipole interaction respectively, the magnons are driven directly by a strong microwave field simultaneously. Frist, the intensity of driving magnetic field which can reach the threshold condition of phonon laser is given. Then, we demonstrate that the adjustable external magnetic field can be used as a good control method to the phonon laser. Compared with phonon laser in optomechanical systems, our scheme brings a new degree of freedom of manipulation. Finally, with the experimentally feasible parameters, threshold power in our scheme is close to the case of optomechanical systems. Our study may inspire the field of magnetically controlled phonon lasers.