Dynamics of curved domain walls in hexagonal magnetostrictive materials with nonlinear dissipation and Rashba effects

Spin-dependent transport in long semiconductor heterostructures with Rashba effect: A Green’s function approach

The inherent compromise between charge mobility and phonon transport necessitates hierarchical structural modularity to achieve a high figure-of-merit (ZT) in homogeneous materials. Herein, shifting our focus from conventional grain boundaries to grain interiors, we leverage configurational entropy and metavalent bonding to design a novel SnAgBiTeSe2 solid solution alloy with a single cubic crystal structure, representing a true hetero-composition/homo-structure (heC/hoS) system. Due to its highly polarizable metavalent bonds, the material maintains a uniform macroscopic symmetry, with strain fluctuations at the nanoscale preventing macroscopic phase separation. This dual mechanism strongly suppresses phonon propagation without significantly compromising charge transport. Its electronic structure exhibits a pronounced Rashba effect, which simultaneously modulates both valley and spin degeneracies. This leads to the formation of highly converged, multi-spin-split bands that facilitate efficient charge carrier transport. Moreover, owing to the suppression of BiAg antisite defect enabled by the heC/hoS architecture, slight Ag doping successfully induces rare p-type conductivity. These features collectively yield a record-low lattice thermal conductivity (κl=0.35 Wm-1K-1 at 300 K) and high ZT values of 0.42 at 300 K and 0.6 at 402 K for SnAg1.03Bi0.97TeSe2, outperforming all reported AgBiSe2-based counterparts across the 300-500 K temperature window.

KTaO 3 (KTO) is an incipient ferroelectric, characterized by a softening of the lowest transverse optical (TO) mode with decreasing temperature. Cooper pairing in the recently discovered KTO-based heterostructures has been proposed to be mediated by the soft TO mode. Here, we study the electron coupling to the zone-center odd-parity modes of bulk KTO by means of relativistic Density Functional Perturbation Theory (DFPT). The coupling to the soft TO mode is by far the largest, with comparable contributions from both intraband and interband processes. Remarkably, we find that for this mode, spin nonconserving matrix elements are particularly relevant. We develop a three-band microscopic model with spin-orbit-coupled t 2 g orbitals that reproduces the main features of the results. For the highest energy band, the coupling can be understood as a “dynamical” isotropic Rashba effect. In contrast, for the two lowest bands, the Rashba-like coupling becomes strongly anisotropic. The DFPT protocol implemented here enables the calculation of the full electron-phonon coupling matrix projected onto any mode of interest, and it is easily applicable to other systems.

Composite quantum compounds (CQCs) provide a platform to explore the mutual interplay between seemingly independent physical phenomena, providing new insights into their coupled behavior. In particular, the giant Rashba effect, ferroelectric switching and non-trivial band topology represent symmetry-driven, local and global characteristics of materials, respectively, thereby offering both novel functionalities and deeper insight into fundamental physics. In present work, we investigated CsSiBi and CsPbSb compounds for potential CQCs withinfirst-principlescalculations using Vienna ab-initio simulation package and WIEN2k with symmetry analysis. The stability of both compounds is systematically examined by evaluating their chemical, mechanical, dynamical and thermal characteristics. The CsSiBi coined as intrinsic CQC with topological insulating phase, Rashba spin-splitting and ferroelectric switching while CsPbSb limited to very large isotropic Rashba effect. The spin-texture reversal, large polarization and ferroelectric double well energy profile validate the ferroelectricity and facilitates the electrical manipulation for spin degrees of freedom in new CQC CsSiBi. The calculated values ofαRΓ-MandαRΓ-Kfor CsSiBi (CsPbSb) are 2.46 eV Å (5.71 eV Å) and 2.47 eV Å (5.71 eV Å), respectively which indicates giantisotropicRashba effect. Our study also validates the recent reports on enhanced reliability of full-potential codes in analyzing electronic band structure of materials exhibiting surface-induced asymmetry. The confluence of aforementioned properties open avenues for more reliable next-generation multifunctional materials for spintronics and nanoelectronics.

ABSTRACT Organic–inorganic halide perovskites have emerged as promising materials for next‐generation optoelectronic devices due to their exceptional photophysical properties. Among them, α‐formamidinium lead tri‐iodide (α‐FAPbI 3 ) with a cubic symmetry (space group of ) has garnered attention as a potential absorber in solar cells for its narrow bandgap and superior stability. The fundamental mechanisms governing its high performance have yet to be fully elucidated. In this study, we demonstrate that centrosymmetry breaking in [001] preferentially oriented α‐FAPbI 3 thin films (POF) arises from inevitable anisotropic strain during film formation. Using circular polarization‐dependent pump‐probe transient absorption spectroscopy, we observe Rashba‐type band splitting exclusively in POF, indicating symmetry breaking. Angle‐dependent X‐ray diffraction and photoluminescence (PL) reveal significant residual stress in POF compared to randomly oriented films (ROF), confirming strain‐induced lattice distortion. Furthermore, time‐resolved PL and microwave conductivity measurements reveal top‐back inhomogeneous carrier dynamics and anisotropic charge carrier mobility, supporting the presence of the anisotropic strain‐induced symmetry breaking. Our findings provide direct experimental evidence that inevitable strain in POF induces static Rashba effects, offering new insights into strain engineering for high‐performance perovskite optoelectronics and potential quantum applications.

Abstract The Rashba effect, originating from spin-orbit interaction and crystal asymmetry, enables electric-field control of electron spins, making materials with strong Rashba splitting near the Fermi level attractive for spintronics. Using first-principles calculations, we identify asymmetric Bi 2 O 2 Se monolayer as a semiconductor exhibiting large Rashba splitting. Its structure induces a work function difference (Δ ϕ ) of 3.25 eV, dipole moment of 0.32 D, and a small band gap of 0.30 eV. The conduction band shows Rashba energy E R = 33.6 meV and coupling constant α R = 10.56 eV Å with circular spin texture around the Γ point. The monolayer remains mechanically stable under ± 10% strain, while strain and electric fields (≤0.3 V/Å) reversibly tune polarization and Rashba splitting. A finite out-of-plane spin component ( S z ) emerges from anisotropic SOC, demonstrating experimentally feasible and controllable spin-texture modulation. Both E R and α R increase under tensile strain, highlighting Bi 2 O 2 Se’s potential for high-efficiency spin-field-effect transistors and advanced semiconductor spintronics.

With mature fabrication technologies and tunable spin relaxation, IIIV semiconductor two-dimensional quantum structures serve as a preferred material system for developing spintronic devices. This paper reviews the progress in manipulating spin-orbit coupling and spin relaxation in two-dimensional electron gas and two-dimensional hole gas systems via structural design, electric fields, and strain. By combining time-resolved magneto-optical spectroscopy with magnetotransport measurements, we analyze the synergistic modulation of Rashba and Dresselhaus effects to optimize the spin lifetime and highlight the distinct physical pathways for constructing long-lived SU(2) spin states in zinc-blende GaAs and wurtzite GaN heterostructures. For zinc-blende GaAs quantum wells, we discuss the realization of the persistent spin helix state by balancing the Rashba and Dresselhaus effects through structural design and electric field control. In contrast, for wurtzite GaN systems, we reveal that the Rashba and Dresselhaus effects inherently share the same symmetry form, allowing for the direct cancellation of effective magnetic fields to achieve a robust SU(2) electronic state. Ultimately, this comprehensive physical picture provides a scientific basis for material selection and architecture design in future high-performance spintronic devices.

Quantized conductance in quasi-one-dimensional systems not only provides a hallmark of ballistic transport, but also serves as a gateway for exploring quantum phenomena. Recently, a unique hidden Rashba effect, which arises from the compensation of opposite spin polarizations of a Rashba bilayer in inversion symmetric crystals with dipole fields, such as bismuth oxyselenide (Bi_{2}O_{2}Se), has attracted tremendous attention. However, investigating this effect utilizing conductance quantization remains challenging. Here we report the conductance quantization observed in a chemical vapor deposition (CVD)-grown high-mobility Bi_{2}O_{2}Se nanoribbon, where quantized conductance plateaus up to 44×2e^{2}/h (e is the elementary charge, h is the Planck's constant, and the factor 2 results from spin degeneracy) are achieved at zero magnetic field. Because of the hidden Rashba effect, the quantized conductance remains in multiples of 2e^{2}/h without Zeeman splitting even under magnetic field up to 12T. Moreover, within a specific range of magnetic field, the plateau sequence follows the Pascal triangle series, namely, (1,3,6,10,15…)×2e^{2}/h, reflecting the interplay of size quantization in the two transverse directions. These observations are well captured by an effective hidden Rashba bilayer model. Our results demonstrate Bi_{2}O_{2}Se as a compelling platform for spintronics and the investigation of emergent phenomena.

The total Zeeman and Rashba magnetoconductances (G=G↑↑+G↑↓) in quantum wire, quantum point contact and open quantum dot, they do not naturally display spin changes (flipping and polarizations) in the line form, especially at the perturbative limit; this was only observed theoretically in the contributions (spin conductances):G↑↑andG↑↓. Here in this work, we study the possibility of directly observing the induced spin changes in the total magnetoconductance (perturbative limit), which would be an important tool for monitoring the spin in electron magnetotransport experiments. Using three-dimensional magnetoconductance,G(ϕ/ϕo,E), with locally applied Zeeman or Rashba effects (defined with an extensionL), we are able to detect spin changes directly in the total conductance, using variations ofLin conjunction with the application of a controllable impurity. Here using electrons with spin up, as incident electrons, the spin change (spin flipping) is observed whenG↑↓becomes dominant, generating Fabry-Pérot type ripples in the total conductance,G. These ripples are associated with asymmetries in the spin contributions, induced by the controllable impurity. This controllable impurity reveals spin changes (high up or down polarizations) through asymmetries detected in the induced ripples. Theϕ/ϕonumber of flux quanta in the limit studied here is used only to couple to the spin change generator and also to make the signatures better defined. The signatures studied here are also observed forϕ/ϕo=0.

Antiferromagnetic (AFM) materials provide a platform to couple altermagnetic (AM) spin-splitting with the magneto-optical Kerr effect (MOKE), offering potential for next-generation quantum technologies. In this work, first-principles calculations, symmetry analysis, and k·p modeling are employed to show that interlayer sliding in AFM multiferroic bilayers enables control of electronic, magnetic, and magneto-optical properties. This study reveals an intriguing dimension-driven AM crossover: the 2D paraelectric (PE) bilayer exhibits spin-degenerate bands protected by the spin-space symmetry, whereas the 3D counterpart manifests AM spin-splitting along kz ≠ 0 paths. Furthermore, interlayer sliding breaks this symmetry and stabilizes a ferroelectric (FE) state with compensated ferrimagnetism, where the Zeeman-like field is responsible for the nonrelativistic spin-splitting. In the FE phase, spin-orbit coupling (SOC) lifts accidental degeneracies and produces "alternating" spin-polarized bands through the interplay of Zeeman and Rashba effects. Crucially, spin polarization, ferrovalley polarization (ΔEV), and the Kerr angle (θk) can all be reversed by switching either sliding ferroelectricity or the Néel vector. Our findings reveal the rich coupling among electronic, magnetic, and optical orders in sliding multiferroics, illustrating new prospects for ultralow-power spintronic and optoelectronic devices.

The quantum Hall effect is one of the most fundamental quantum phenomena in condensed matter physics, and via tuning the quantum Hall states (QHSs), the evolution of band topologies and electron correlations can be investigated and revealed therein. However, for the vast majority of QHS systems, even- and odd-integer quantized plateaus coexist and cannot be effectively regulated. Here, we demonstrate field-effect-tunable even-odd transition of QHSs in a fixed two-unit-cell-thick (2-uc-thick) Bi_{2}O_{2}Se film, which is unlike irreversible thickness-controlled approaches [J. Wang et al., Even-integer quantum Hall effect in an oxide caused by a hidden Rashba effect, Nat. Nanotechnol. 19, 1452 (2024)NNAABX1748-338710.1038/s41565-024-01732-z]. Only even-integer quantized plateaus are observed in the 2-uc-thick epitaxial film on SrTiO_{3} when the quantum oscillations show degenerated spin splitting under positive gate voltages. In contrast, the simultaneous emergence of even- and odd-integer QHSs is achieved under negative gate voltages, accompanied with significant spin splitting. Theoretical calculations reveal that this reversible switching stems from gate-controlled inversion symmetry breaking that modulates the splitting of Landau levels. This Letter demonstrates the significant tunability of electrostatic gating in altering inversion symmetry and modulating electron correlations in Rashba-type 2-uc-thick Bi_{2}O_{2}Se, enabling dynamic control of QHSs parity without structural changes, thereby extending the potential applications to fractional statistics and spintronics.

Rashba spin–orbit coupling-induced spin–momentum locking is a key mechanism enabling the development of spin field-effect transistors (spinFETs) for fast and energy-efficient computing. Recent studies have demonstrated the presence of spin–momentum locking via the local Rashba effect in the two-dimensional (2D) semiconducting material PtSSe, making it a promising candidate for 2D spinFET design. However, forming a high-quality interface between bulk ferromagnetic metals and PtSSe remains challenging due to the emergence of metal-induced gap states (MIGSs), which are caused by dangling bonds at the contact interface. To address this issue and enhance contact performance, a graphene-buffered vertical heterostructure comprising Co and PtSSe was theoretically designed using first-principles density functional theory calculations. The results show that introducing a graphene interlayer effectively suppresses MIGSs and significantly lowers the Schottky barrier height (SBH) at the Co/PtSSe interface. Moreover, the variation in SBH under an applied out-of-plane electric field shows a steeper slope in the graphene-inserted heterostructure compared to the direct Co/PtSSe contact. This indicates better gate tunability. In addition, a significant change in the Rashba parameter is observed under the external electric field. This combined tunability of SBH and Rashba parameters under an applied electric field provides a promising route for achieving a low subthreshold swing and a high ON/OFF current ratio in spinFETs. The presence of the graphene interlayer also greatly improves the spin polarization at the contact interface. These results provide important guidance for the design and development of advanced spinFET devices.

Rashba effect of polaron in a triangular quantum well

The Rashba effect has emerged as a pivotal phenomenon driving novel discoveries in condensed matter physics. Materials with large Rashba energy ER, wavenumber offset k0 and Rashba parameter αR are prerequisites for spintronic devices operating above room temperature. While neither ultrathin GeTe films (<3.0 nm thickness) nor monolayer topological insulator Bi2Te3 (1 quintuple layer (QL) on Si(111)) manifest Rashba splitting, An unprecedented strength of Rashba effect with ER=0.57±0.03eV, k0=0.16±0.03Å−1 and αR=6.86±0.59eV·Å in GeTe (1 nm)/Bi2Te3 (1 QL) heterostructure is achieved. The spin‐momentum‐locked bands resulting from the Rashba effect of GeTe /Bi2Te3 is confirmed by density functional theory (DFT) calculations. In GeTe (x nm)/Bi2Te3(10 QL), it is find that the values of ER, k0 and αR significantly enhance as the thickness of GeTe decreases contrasting with GeTe films. By comparing the thickness dependence of GeTe with that of GeTe/Bi2Te3, it is determined that the enhanced Rashba parameter ΔαR is proportional to the electric field in the GeTe/Bi2Te3 heterojunction region. It is concluded that the origin of this huge Rashba effect is attributed to the strong band bending in the GeTe/Bi2Te3 heterojunction region, where the striking inversion‐symmetry‐breaking and significant bandgap difference result in a sharp potential gradient normal to the interface. This work opens an avenue to enhance the Rashba splitting by strong band bending and design spin field effect transistors with spin channel as short as several nanometer scales.

Quasiparticles in solids may carry charge and spin. Recent theoretical and experimental studies found that quasiparticles may carry additional types of angular momentum. Conduction electrons in solids may carry orbital angular momentum and phonons may also carry angular momentum, which amounts to the circular or elliptic vibration of atoms. In addition, quasiparticle angular momentum may play significant roles in various phenomena in solids. Studies towards this direction may find useful device applications. This work summarizes recent development in the field of orbitronics with focus on its theoretical aspects. The discussed topics include the electron orbital Rashba effect, electron orbital dynamics, phonon angular momentum, and magnon angular momentum.

Abstract As we advance towards next-generation quantum technologies characterized by coherence, entanglement, and quantum control, chemistry is emerging as a critical enabler of quantum material innovation. This perspective explores how modern chemical strategies provide atomic-level control over material properties, allowing deterministic design of quantum states and interfaces. We highlight recent advances in spin-active molecules, quantum dots, two-dimensional materials, and hybrid platforms where chemistry shapes coherence, coupling, and device integration. Tools such as coordination chemistry, defect engineering, and surface passivation are shown to directly impact quantum behaviour, while chemical theory and spectroscopy enable deep insight into structure–function relationships. Through case studies ranging from strain-induced Rashba effects to single-atom manipulation, we illustrate how chemistry transcends traditional roles to become a central architect of quantum technologies. We argue for a new paradigm of ‘quantum-informed chemistry’ as essential for designing scalable, high-fidelity systems for quantum sensing, computation, and communication.

This perspective article explores the potential of two-dimensional electron and hole gases at oxide/oxide interfaces as promising conduction channels in energy-efficient spintronic devices for memory and logic applications. Magneto-electric and ferro-electric device architectures are considered, highlighting their advantages in integrating non-volatility with ultra-fast switching capabilities. We emphasize the significance of spin-orbit coupling in generating robust spin currents and examine how the Rashba and inverse Edelstein effects can be harnessed in device operations. Specific heterostructures, including HfO2/SrTiO3, Cr2O3/TiO2-x, and ZrO2-x-based systems, are reviewed in terms of their material properties, interface stability, and suitability for practical implementation.

The Rashba effect, which plays a crucial role in fundamental materials physics and potential spintronics applications, has been engineered in diverse systems, including semiconductor quantum wells, oxide heterostructures, metallic surfaces, topological insulators, ferroelectrics, etc. However, generating it in systems that preserve bulk inversion symmetry (BIS), for example, in bulk metals, has not been possible so far. We demonstrate a strategy to introduce and tune Rashba spin-orbit interaction (SOI) to unprecedented magnitudes in inversion-symmetric solids by incorporating ultrasmall silver nanoparticles in bulk gold. The near-identical lattice constants of Ag and Au allow dense packing of the Ag/Au hetero-interfaces without compromising the global BIS. By varying the density of embedded nanoparticles, we generate Rashba SOI in a bulk metal with coupling strength ~15 meV∙Å, higher than any known system preserving BIS globally, and show up to ~20 times increase in the spin-orbit scattering rate. We argue that the combined effect of charge transfer at the interfaces and polaronic localization enhances the SOI.

Abstract We investigate the bulk-boundary correspondence in two-dimensional type-I semi-Dirac materials with band inversion and Rashba spin–orbit coupling (SOC). Employing a dimensional reduction framework, we identify the Zak phase along the quadratically dispersing direction as a topological invariant that captures the presence of edge states. In the non-trivial topological regime, systems with finite width exhibit energy-dependent edge states that are topologically protected only at specific momenta. At k x = 0 , symmetry-protected edge states emerge, analogously to the Rashba-free case. At finite k x , the interplay of SOC and band structure gives rise to spin-dependent edge states, localized on specific edges based on its spin and particle-hole character. We computed spin-resolved conductance through these edge channels and observed robust, tunable oscillations-attributable to spin precession induced by the effective Rashba magnetic field. These results reveal how spin-orbit interactions enrich the edge physics of semi-Dirac systems and provide a platform for spintronic control in anisotropic topological materials.