The Rashba-Dresselhaus effect is the splitting of doubly degenerate band extrema in semiconductors, accompanied by the emergence of counter-rotating spin textures and spin-momentum locking. Here we investigate how this effect is modified by lattice vibrations. We show that, in centrosymmetric non-magnetic crystals, for which a bulk Rashba-Dresselhaus effect is symmetry-forbidden, electron-phonon interactions can induce a phonon-assisted, dynamic Rashba-Dresselhaus spin splitting in the presence of an out-of-equilibrium phonon population. In particular, we show how Rashba, Dresselhaus, or Weyl spin textures can selectively be established by driving coherent infrared-active phonons, and we perform ab initio calculations to quantify this effect for halide perovskites.
A major impediment towards realizing technologies based on the emerging principles of antiferromagnetic spintronics is the shortage of suitable materials. In this paper, we propose a design of polar|nonpolar heterostructures of perovskite oxides, where a single unit cell of SrIrO3 is sandwiched between a thin film of LaAlO3 and a substrate of SrTiO3. Our calculations within the framework of density-functional theory + Hubbard U + spin-orbit coupling reveal a two-dimensional conducting layer with electron and hole pockets at the interface, exhibiting a strong anisotropic Rashba-Dresselhaus effe…
We investigate theoretically the spin transport in two-terminal mesoscopic rings in the presence of both the Rashba spin-orbit interaction (RSOI) and the Dresselhaus spin-orbit interaction (DSOI). We find that the interplay between the RSOI and DSOI breaks the original cylindric symmetry of mesoscopic ring and consequently leads to the anisotropic spin transport, i.e., the conductance is sensitive to the positions of the incoming and outgoing leads. The anisotropic spin transport can survive even in the presence of disorder caused by impurity elastic scattering in a realistic system.
We have investigated the complex two-dimensional electron system with unequal Rashba and Dresselhaus spin-orbit interactions in the presence of a perpendicular magnetic field. The spin polarizations are obtained in a wide range of magnetic fields. It is shown that such a system is hard to be magnetized. We also find that the resonant charge and spin Hall conductances occurs simultaneously at a certain magnetic field, at which two (nearly) degenerate Landau levels are filled partly. The resonant Hall effects are universal in this type of semiconductor materials, and could have potential applica…
We have developed a method to systematically compute the form of Rashba- and Dresselhaus-like contributions to the spin Hamiltonian of heterostructures to an arbitrary order in the wavevector k. This is achieved by using the double group representations to construct general symmetry-allowed Hamiltonians with full spin-orbit effects within the tight-binding formalism. We have computed full-zone spin Hamiltonians for [001]-, [110]- and [111]-grown zinc blende heterostructures (D_{2d},C_{4v},C_{2v},C_{3v} point group symmetries), which are commonly used in spintronics. After an expansion of the H…
We calculate the longitudinal and spin-Hall conductances in four-lead bridges with Rashba - Dresselhaus spin-orbit interactions. Numerical results are obtained both within Landauer-Buttiker formalism and by the direct evaluation of the Kubo formula. The microscopic Hamiltonian is obtained in the tight-binding approximation in terms of the neareast-neighbor hopping integral $t$, the Rashba spin-orbit coupling $V_R$, the Dresselhaus spin-orbit coupling $V_D$ and an Anderson-like, on-site disorder energy strength $W$. We reconfirm that below a critical disorder threshold, the spin-Hall effect is …
It has been recently suggested that the coexistence of ferroelectricity and Rashba-like spin-splitting effects due to spin-orbit coupling in a single material may allow for a non-volatile electric control of spin degrees of freedom. In the present work, we compared the structural and ferroelectric properties of tetragonal and rhombohedral phases of ferroelectric BiAlO$_3$ by means of density-functional calculations. In both phases, we carefully investigated Rashba and Dresselhaus effects, giving rise to spin-splitting in their bulk electronic structure, particularly near the conduction band mi…
Bulk hybride halide perovskites are governed by significant Rashba and Dresselhaus splitting. This indicates that such effects will not only affect their optoelectronic properties but also those of their two dimensional layered relatives. This work aims at understanding how different ways of symmetry breaking influence these effects in those materials. For this purpose, model structures are adopted where the organic compounds are replaced by Cs atoms. Disregarding possible distortions in the inorganic layers, results in structures with composition Cs$_{n+1}$Pb$_n$I$_{3n+1}$. Using the all-elec…
Aiming at the optimization of the spin diffusion length in (001) GaAs quantum wells, we explore the effect of the anisotropy of the spin-orbit coupling on the competition between the Rashba and the Dresselhaus spin-orbit couplings by solving the kinetic spin Bloch equations with the electron-phonon and the electron-electron scattering explicitly included. For identical strengths of the Rashba and the Dresselhaus spin-orbit couplings, the spin diffusion length shows strong anisotropy not only for the spin polarization direction but also for the spin diffusion direction. Two special directions a…
We derive an effective Hamiltonian for a (001)-confined quasi-two-dimensional hole gas in a strained zincblende semiconductor heterostructure including both Rashba and Dresselhaus spin-orbit coupling. In the presence of uniaxial strain along the $\left\langle110\right\rangle$ axes, we find a conserved spin quantity in the vicinity of the Fermi contours in the lowest valence subband. In contrast to previous works, this quantity meets realistic requirements for the Luttinger parameters. For more restrictive conditions, we even find a conserved spin quantity for vanishing strain, restricted to th…
In this note, we show that the latest spin grating measurement of spin helix by Koralek {\em et al.} [Nature {\bf 458}, 610 (2009)] provides strong evidence of the infinite spin diffusion length of any spin polarization along the direction perpendicular to the effective magnetic field from the Dresselhaus and Rashba spin-orbit couplings with identical strengths in $(001)$ GaAs quantum wells, predicted by Cheng {\em et al.} [Phys. Rev. B {\bf 75}, 205328 (2007)].
It is well known that the Dresselhaus spin-orbit coupling (SOC) in semiconductor two dimensional electron gases (2DEGs) possesses both linear and cubic in momentum contributions. Nevertheless, the latter is usually neglected in most theoretical studies. However, recent Kerr rotation experiments have revealed a significant enhancement of the cubic Dresselhaus interaction by increasing the drift velocities in 2DEGs hosted in GaAs quantum wells. Here, we present a study of the optical spin Hall conductivity in 2DEGs under the simultaneous presence of Rashba and (linear plus cubic) Dresselhaus SOC…
We study magnetic textures realized in noncentrosymmetric Kondo lattice models, in which localized magnetic moments weakly interact with itinerant electrons subject to Rashba and Dresselhaus spin-orbit couplings. By virtue of state-of-the-art numerical simulations as well as variational calculations, we uncover versatile multiple-$Q$ orderings under zero magnetic field, which are found to originate in the instabilities of the Fermi surface whose spin degeneracy is lifted by the spin-orbit couplings. In the case with equally-strong Rashba and Dresselhaus spin-orbit couplings, which is known to …
Generating and controlling spin current (SC) are of central interest in spin physics and applications. To date, the spin-orbit interaction (SOI) is an established pathway to generate SC through the spin-charge current conversion. We predict an efficient spin-light conversion via the Rashba and higher-order cubic Dresselhaus SOIs in ferroelectrics. Different from the known Edelstein effect, where SC is created by the nonequilibrium spin density, our predicted spin-polarized current is from direct interactions between light and unique spin textures generated by SOI in ferroelectrics. Using first…
Ruddelsden-Popper halide perovskites are highly versatile quasi-two-dimensional energy materials with a wide range of tunable optoelectronic properties. Here we use the all-inorganic Cs$_{n+1}$Pb$_n$X$_{3n+1}$ Ruddelsden-Popper perovskites with X=I, Br, and Cl to systematically model the effect of octahedral tilting distortions on the energy landscape, band gaps, macroscopic polarization, and the emergence of Rashba-/Dresselhaus splitting in these materials. We construct all unique $n=1$ and $n=2$ structures following from octahedral tilts and use first-principles density functional theory to …
Spin relaxation under identical Dresselhaus and Rashba coupling strengths in GaAs quantum wells is studied in both the traditional collinear statistics, where the energy spectra do not contain the spin-orbit coupling terms, and the helix statistics, where the spin-orbit couplings are included in the energy spectra. We show that there is only marginal difference between the spin relaxation times obtained from these two different statistics. We further show that with the cubic term of the Dresselhaus spin-orbit coupling included, the spin relaxation time along the (1,1,0) direction becomes finit…
Inorganic-organic lead halide perovskites, particularly methylammonium lead halide (MAPbI$_3$) perovskite, is perceived to be a promising material for optoelectronics and spintronics. However, lead toxicity and instability under air and moisture restrict its practical uses. Hence, it is essential to reduce lead extent by substituting appropriate alternatives. Here, we substitute Sn and Ge in cubic MAPbI$_3$ and compare various properties of hybrid perovskites by employing state-of-the-art first-principles-based methodologies, viz., density functional theory (DFT) with semilocal and hybrid func…
Despite the imperative importance in solar-cell efficiency, the intriguing phenomena at the interface between perovskite solar-cell and adjacent carrier transfer layers are hardly uncovered. Here we show that PbI$_2$/AI-terminated lead-iodide-perovskite (APbI$_3$; A=Cs$^+$/ methylammonium(MA)) interfaced with the charge transport medium of graphene or TiO2 exhibits the sizable/robust Rashba-Dresselhaus (RD) effect using density-functional-theory and ab initio molecular dynamics (AIMD) simulations above cubic-phase temperature. At the PbI$_2$-terminated graphene/CsPbI3(001) interface, ferroelec…
One of the major strategies to control magnetism in spintronics is to utilize the coupling between electron spin and its orbital motion. The Rashba and Dresselhaus spin-orbit couplings induce magnetic textures of band electrons called spin momentum locking, which produces a spin torque by the injection of electric current. However, joule heating had been a bottleneck for device applications. Here, we propose a theory to generate further rich spin textures in insulating antiferromagnets with broken spatial inversion symmetry (SIS), which is easily controlled by a small magnetic field. In antife…
A spin-rotation symmetry in spin-orbit coupled two-dimensional electron systems gives rise to a long-lived spin excitation that is robust against short-range impurity scattering. The influence of a constant in-plane electric field on this persistent spin helix is studied. To probe the field-induced eigen-modes of the spin-charge coupled system, a surface acoustic wave is exploited that provides the wave-vector for resonant excitation. The approach takes advantage of methods worked out in the field of space-charge waves. Sharp resonances in the field dependence of the in-plane and out-of-plane …
Ferroelectric Rashba semiconductors (FERSC) are a novel class of multifunctional materials showing a giant Rashba spin splitting which can be reversed by switching the electric polarization. Although they are excellent candidates as channels in spin field effect transistors, the experimental research has been limited so far to semiconducting GeTe, in which ferroelectric switching is often prevented by heavy doping and/or large leakage currents. Here, we report that CsBiNb2O7, a layered perovskite of Dion-Jacobson type, is a robust ferroelectric with sufficiently strong spin-orbit coupling and …
The spin Hall effect is investigated in a high mobility two dimensional electron system with the spin-orbital coupling of both the Rashba and the Dresselhaus types. A spin current perpendicular to the electric field is generated by either the Rashba or the Dresselhaus coupling. The spin Hall conductance is independent of the stength of the coupling, but its sign is determined by the relative ratio of the two couplings. The direction of spin current is controllable by tuning the magnitude of the surface electric field perpendicular to the two dimensional plane via adjusting the Rashba coupling.…
We develop the microscopic theory of electron spin dephasing in (110)-grown quantum wells where the electron scattering time is comparable to or exceeds the period of spin precession in the effective magnetic field caused by spin-orbit coupling. Structures with homogeneous and fluctuating Rashba field, which triggers the dephasing of electron spins aligned along the growth direction, are analyzed. We show that the Dresselhaus field, which is always present in zinc-blende-type quantum wells, suppresses the spin dephasing enabling very long spin lifetime of conduction electrons. The dependence o…
In this work we analytically investigate the longitudinal optical conductivity of the C$_{2v}$ symmetric topological insulator. The conductivity expressions at $ T = 0 $ are derived using the Kubo formula and expressed as a function of the ratio of the Dresselhaus and Rashba parameters that characterize the low-energy Hamiltonian. We find that the longitudinal inter-band conductivity vanishes when Dresselhaus and Rashba parameters are equal in strength, also called the persistent spin helix state. The calculations are extended to obtain the frequency-dependent real and imaginary components of …
We investigate theoretically how the spin-orbit Dresselhaus and Rashba effects influence the electronic structure of quasi-one-dimensional semiconductor quantum dots, similar to those that can be formed inside semiconductor nanorods. We calculate electronic energy levels, eigen-functions, and effective g-factors for coupled, double dots made out of different materials, especially GaAs and InSb. We show that by choosing the form of the lateral confinement, the contributions of the Dresselhaus and Rashba terms can be tuned and suppressed, and we consider several possible cases of interest. We al…
Spin dependent transport in a multi-terminal mesoscopic ring is investigated in presence of Rashba and Dresselhaus spin-orbit interactions. Within a tight-binding framework we use a general spin density matrix formalism to evaluate all three components ($P_x$, $P_y$ and $P_z$) of the polarization vector associated with the charge current through the outgoing leads. It explores the dynamics of the spin polarization vector of current propagating through the system subjected to the Rashba and/or the Dresselhaus spin-orbit couplings. The sensitivity of the polarization components on the electrode-…
We have confirmed the k-dependent spin splitting in wurtzite AlxGa1-xN/GaN heterostructures. Anomalous beating pattern in Shubnikov-de Haas measurements arises from the interference of Rashba and Dresselhaus spin-orbit interactions. The dominant mechanism for the k-dependent spin splitting at high values of k is attributed to Dresselhaus term which is enhanced by the Delta C1-Delta C3 coupling of wurtzite band folding effect.
We consider stationary spin current in a (110)-oriented GaAs-based symmetric quantum well due to a nonlinear response to an external periodic electric field. The model assumed includes the Dresselhaus spin-orbit interaction and the random Rashba spin-orbit coupling. The Dresselhaus term is uniform in the quantum well plane and gives rise to spin splitting of the electron band. The external electric field of frequency $ω$ - in the presence of random Rashba coupling -- leads to virtual spin-flip transitions between spin subbands, generating stationary pure spin current proportional to the square…
Spin-orbit coupling (SOC) in conjunction with broken inversion symmetry acts as a key ingredient for several intriguing quantum phenomena viz. persistent spin textures, topological surface states and Rashba-Dresselhaus (RD) effects. The coexistence of spontaneous polarization and the RD effect in ferroelectric materials enables the electrical control of spin degree of freedom. In light of this, we explore here the ferroelectric lead halide perovskite viz. CsPbF$_3$ as a potential candidate in the field of spintronics by employing state-of-the-art first-principles based methodologies viz. densi…
It was recently shown that a spatially modulated Rashba spin-orbit coupling in a quantum wire drives a transition from a metallic to an insulating state when the wave number of the modulation becomes commensurate with the Fermi wave length of the electrons in the wire. It was suggested that the effect may be put to practical use in a future spin transistor design. In the present article we revisit the problem and present a detailed analysis of the underlying physics. First, we explore how the build-up of charge density wave correlations in the quantum wire due to the periodic gate configuratio…
Spin splitting of energy bands can be induced by relativistic spin-orbit interactions in materials without inversion symmetry. Whereas polar space group symmetries permit Rashba (R-1) spin splitting with helical spin textures in momentum space, which could be reversed upon switching a ferroelectric polarization via applied electric fields, the ordinary Dresselhaus effect (D-1A) is ac-tive only in materials exhibiting nonpolar noncentrosymmetric crystal classes with atoms occupy-ing exclusively non-polar lattice sites. Consequently, the spin-momentum locking induced by D-1A is not electric fiel…
We study ultrafast photocurrents in thin films of a model ferromagnetic metal with broken bulk inversion symmetry, the half-metallic Heusler compound NiMnSb, following excitation with an optical pump pulse with photon energy 1.55 eV. Remarkably, in terms of the direction of the sample magnetization M, all photocurrents are found to be a superposition of a component with Rashba- and Dresselhaus-type symmetry. We explain the Dresselhaus bulk photocurrent as follows: Pump-induced electron heating induces an excess of spin μ_s||M, which transfers spin angular momentum into states with Dresselhaus-…
The momentum-dependent Rashba and Dresselhaus spin-splitting has gained much attention for its highly promising applications in spintronics. In the present work, ab initio density functional theory calculations are performed to study the spin-splitting effect in ferroelectric oxide perovskite KIO3. Our calculations are additionally supported by symmetry adapted two-band k.p Hamiltonian. Non-negligible spin-splitting effect is observed at conduction band minimum (CBm) and valence band maximum (VBM) for rhombohedral R3m and R3c phases. Linear Rashba terms successfully explain the splitting at VB…
We demonstrate that the size of the electric-field-induced Rashba spin splitting in an 80 nm wide modulation-doped InGaSb quantum well can depend strongly on the spatial variation of the electric field. In a slightly asymmetric quantum well it can be an order of magnitude stronger than for the average uniform electric field. For even smaller asymmetry spin subbands can have wave functions and/or expectation values of the spin direction that are completely changed as the in-plane wave vector varies. The Dresselhaus effect can give an anticrossing at which the spin rapidly flips.
Spin-orbit coupling effects occurring in non-centrosymmetric materials are known to be responsible for non-trivial spin configurations and a number of emergent physical phenomena. Ferroelectric materials may be especially interesting in this regard due to reversible spontaneous polarization making possible for a non-volatile electrical control of the spin degrees of freedom. Here, we explore a technologically relevant oxide material, HfO2, which has been shown to exhibit robust ferroelectricity in a non-centrosymmetric orthorhombic phase. Using theoretical modelling based on density-functional…
