Journal articles on the topic 'Giant Rashba-type spin splitting'

The Rashba effect is one of the most striking manifestations of spin-orbit coupling in solids and provides a cornerstone for the burgeoning field of semiconductor spintronics. It is typically assumed to manifest as a momentum-dependent splitting of a single initially spin-degenerate band into two branches with opposite spin polarization. Combining polarization-dependent and resonant angle-resolved photoemission measurements with density functional theory calculations, we show that the two “spin-split” branches of the model giant Rashba system BiTeI additionally develop disparate orbital textures, each of which is coupled to a distinct spin configuration. This necessitates a reinterpretation of spin splitting in Rashba-like systems and opens new possibilities for controlling spin polarization through the orbital sector.

Strong Rashba effects at semiconductor surfaces and interfaces have attracted attention for exploration and applications. We show with first-principles investigation that applying biaxial stress can cause tunable and giant Rashba effects in ultrathin KTaO₃ (KTO) (001) films.

Coexistence of Rashba-type spin splitting (in-plane spin direction) and band splitting at the K/K′ valleys (out-of-plane spin direction) makes the FRS AgBiP₂Te₆ monolayer a promising candidate for 2D spin FET and spin/valley Hall effect devices.

The influence of the mechanical strain on the electronic structure of the asymmetric (In,Ga)As/GaAs quantum well is considered. Both the direct influence of strain on the orbital part of the electronic structure and an indirect influence through the strain dependent Rashba and Dresselhaus Hamiltonians are taken into account. The analyzed quantum well is taken to have a triangular shape, and is oriented along the <110> direction. For this direction, there exists both the intrinsic and strain-induced spin-orbit interaction. For all analyzed types of spin-orbit interaction, subband splittings depend linearly on the in-plane wave vector. On the other hand, the electronic structure for the Rashba type of the strain-induced spin-orbit interaction shows isotropic dependence in the k-space, while the electronic structure due to the Dresselhaus type shows anisotropy. Furthermore, the Rashba strain-induced spin-orbit interaction increases subband splitting, while the effect of the Dresselhaus Hamiltonian on the electronic structure is opposite to the intrinsic spin-orbit interaction for certain polar angles.

This paper presents a brief review on the ternary phase equilibria in the ternary AV–BVI–I systems (AV = Sb, Bi; BVI = S, Se, Te). These systems includes the series of ternary compounds those are very attractive source materials for photo-, thermos- and ferroelectric energy transformation along the recently discovered semiconductors that exhibit Rashba-type spin splitting in their surface states. In the Rashba semiconductors, a unique toroidal 3D Fermi surface appears on the crystal surface, which leads to unusual properties that make it possible to realize unique electronic devices based on these compounds. The thorough knowledge on the ternary phase diagram of these systems shed light on the chemical and structural design of new multifunctional materials with tunable properties. This knowledge is very important whenfocusing on the chemistry of such multifunctional materials based on complex element systems. REFERENCES Audzijonis A., Sereika R., Ћaltauskas R. 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Due to a strong spin orbit interaction HgTe quantum well structures exhibit an unusual subband structure ordering which leads to some remarkable transport properties depending on the actual carrier density. Especially for quantum wells with an inverted band structure ordering, a strong Rashba-type spin orbit splitting gives rise to a strong spin Hall effect in the metallic regime and in the bulk insulating regime spin polarized edge channel transport leads to the formation of the quantum spin Hall effect. Gated quantum well structures have been used to explore these, the metallic and insulating, transport regimes experimentally.

When monolayer (ML) MoS2 is placed on a substrate, the proximity-induced interactions such as the Rashba spin-orbit coupling (RSOC) and exchange interaction (EI) can be introduced. Thus, the electronic system can behave like a spintronic device. In this study, we present a theoretical study on how the presence of the RSCO and EI can lead to the band splitting, the lifting of the valley degeneracy and to the spin polarization in [Formula: see text]- and [Formula: see text]-type ML MoS2. We find that the maxima of the in-plane spin orientation in the conduction and valence bands in ML MoS2 depend on the Rashba parameter and the effective Zeeman field factor. At a fixed Rashba parameter, the minima of the split conduction band and the maxima of the split valence band along with the spin polarization in ML MoS2 can be tuned effectively by varying the effective Zeeman field factor. On the basis that the EI can be induced by placing the ML MoS2 on a ferromagnetic substrate or by magnetic doping in ML MoS2, we predict that the interesting spintronic effects can be observed in [Formula: see text]- and [Formula: see text]-type ML MoS2. This work can be helpful to gain an in-depth understanding of the basic physical properties of ML MoS2 for application in advanced electronic and optoelectronic devices.

We investigate Anomalous Hall effect in nonmagnetic metal/ferromagnetic insulator bilayer with rotating magnetization of the magnetic insulator. Spin-orbit interaction of Rashba type takes place near metal/insulator interface. Magnetization of the ferromagnetic insulator rotates with some frequency w by microwave radiation under ferromagnetic resonance condition. This rotation together with spin-orbit interaction in non-magnetic metal layer induced Hall current along the interface. The Hall current appears under zero bias in the system. The dependence of Hall current on the exchange splitting, the magnetization rotation frequency and the barrier height is calculated. We analyze various contributions in Hall current and discuss the limit of small frequencies.

On the basis of Lee–Low–Pines unitary transformation, the influence of Rashba spin-orbit (RSO) interaction and Zeeman splitting on the ground state energy of polaron in an asymmetric quantum dot (AQD) is studied by using the variational method of Pekar type. The variations of the absolute ratios of the Zeeman splitting energy and the RSO coupling energy to the ground state energy of polaron with the transverse confinement length (TCL) and the longitudinal confinement length (LCL) of AQD and the magnetic field adjusting length (MFAL) are derived when the RSO interaction and the Zeeman splitting are taken into account. We find the influences of the Zeeman splitting energy and the RSO coupling energy on the ground state energy of a polaron are more dominant when the values of the TCL and the LCL are small. The absolute ratio of the Zeeman splitting energy to the ground state energy rapidly decreases with increasing the MFAL and the absolute ratio of the RSO coupling energy to the ground state energy slowly decreases with increase in MFAL when [Formula: see text], whereas the absolute ratio of the RSO coupling energy to the ground state energy rapidly increases with increase in MFAL when [Formula: see text]. The above results can be attributed to the interesting quantum size confining and spin effects.

Abstract A large and ideal Rashba-type spin-orbit splitting is desired for the applications of materials in spintronic devices and the detection of Majorana Fermions in solids. Here, we propose an approach to achieve giant and ideal spin-orbit splittings through a combination of ordered surface alloying and interface engineering, that is, growing alloy monolayers on an insulating polar surface. We illustrate this unique strategy by means of first-principles calculations of buckled hexagonal monolayers of SbBi and PbBi supported on Al2O3(0001). Both systems display ideal Rashba-type states with giant SO splittings, characterized with energy offsets over 600 meV and momentum offsets over 0.3 Å −1, respectively. Our study thus points to an effective way of tuning spin-orbit splitting in low-dimensional materials to draw immediate experimental interest.

Abstract Spin-orbit coupling (SOC) has gained much attention for its rich physical phenomena and highly promising applications in spintronic devices. The Rashba-type SOC in systems with inversion symmetry breaking is particularly attractive for spintronics applications since it allows for flexible manipulation of spin current by external electric fields. Here, we report the discovery of a giant anisotropic Rashba-like spin splitting along three momentum directions (3D Rashba-like spin splitting) with a helical spin polarization around the M points in the Brillouin zone of trigonal layered PtBi2. Due to its inversion asymmetry and reduced symmetry at the M point, Rashba-type as well as Dresselhaus-type SOC cooperatively yield a 3D spin splitting with αR ≈ 4.36 eV Å in PtBi2. The experimental realization of 3D Rashba-like spin splitting not only has fundamental interests but also paves the way to the future exploration of a new class of material with unprecedented functionalities for spintronics applications.

AbstractNonmagnetic Rashba systems with broken inversion symmetry are expected to exhibit nonreciprocal charge transport, a new paradigm of unidirectional magnetoresistance in the absence of ferromagnetic layer. So far, most work on nonreciprocal transport has been solely limited to cryogenic temperatures, which is a major obstacle for exploiting the room-temperature two-terminal devices based on such a nonreciprocal response. Here, we report a nonreciprocal charge transport behavior up to room temperature in semiconductor α-GeTe with coexisting the surface and bulk Rashba states. The combination of the band structure measurements and theoretical calculations strongly suggest that the nonreciprocal response is ascribed to the giant bulk Rashba spin splitting rather than the surface Rashba states. Remarkably, we find that the magnitude of the nonreciprocal response shows an unexpected non-monotonical dependence on temperature. The extended theoretical model based on the second-order spin–orbit coupled magnetotransport enables us to establish the correlation between the nonlinear magnetoresistance and the spin textures in the Rashba system. Our findings offer significant fundamental insight into the physics underlying the nonreciprocity and may pave a route for future rectification devices.

AbstractA large magnetoresistance was observed in n-type Cdl-xMnxSe (x ≤ 0.10) at low temperatures. The concomitant changes in the Half coefficient as a function of H were also studied. These magnetotransport effects are caused by the s-d interaction. Some specific magnetoresistance mechanisms are discussed. The most likely dominant mechanisms are related to the giant spin splitting of the conduction band.