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The dynamic structure factors reflecting the excitation spectra were investigated in a one-dimensional (1D) optical lattice with a spin-orbit coupling (SOC) effect. The results reveal that the single-particle excitations of both the density and spin dynamical structure factors are strongly reconstructed and split owing to the SOC effect, and a hat-like excitation band appears in the high-binding-energy region. The hat-like excitation band of the density dynamical structure factor exhibits an arc form, and has a pocket in the spin dynamical structure factor. In particular, only a gapless single-particle excitation point is left for both the density dynamical structure factor and the spin dynamical structure factor when the SOC strength reaches a critical point at half-filling. A stronger SOC strength causes the gapless excitation points to disappear, which indicates that the metal-insulator transition occurs. The metal-insulator transition only appears in half-filling and lightly doped regimes.

Ternary transition metal chalcogenides provide a rich platform to search and study intriguing electronic properties. Using angle-resolved photoemission spectroscopy and ab initio calculation, we investigate the electronic structure of Cu2TlX 2 (X = Se, Te), ternary transition metal chalcogenides with quasi-two-dimensional crystal structure. The band dispersions near the Fermi level are mainly contributed by the Te/Se p orbitals. According to our ab-initio calculation, the electronic structure changes from a semiconductor with indirect band gap in Cu2TlSe2 to a semimetal in Cu2TlTe2, suggesting a band-gap tunability with the composition of Se and Te. By comparing ARPES experimental data with the calculated results, we identify strong modulation of the band structure by spin–orbit coupling in the compounds. Our results provide a ternary platform to study and engineer the electronic properties of transition metal chalcogenides related to large spin–orbit coupling.

Weinvestigate the vortex structures excited by Ioffe–Pritchard magnetic field and Dresselhaus-type spin–orbit coupling in F = 2 ferromagnetic Bose–Einstein condensates. In the weakly interatomic interacting regime, an external magnetic field can generate a polar-core vortex in which the canonical particle current is zero. With the combined effect of spin–orbit coupling and magnetic field, the ground state experiences a transition from polar-core vortex to Mermin–Ho vortex, in which the canonical particle current is anticlockwise. For fixed spin–orbit coupling strengths, the evolution of phase winding, magnetization, and degree of phase separation with magnetic field are studied. Additionally, with further increasing spin–orbit coupling strength, the condensate exhibits symmetrical density domains separated by radial vortex arrays. Our work paves the way to explore exotic topological excitations in high-spin systems.

The ground state properties of the rotating Bose–Einstein condensates (BECs) with SU(3) spin–orbit coupling (SOC) in a two-dimensional harmonic trap are studied. The results show that the ferromagnetic and antiferromagnetic systems present three half-skyrmion chains at an angle of 120° to each other along the coupling directions. With the enhancement of isotropic SU(3) SOC strength, the position of the three chains remains unchanged, in which the number of half-skyrmions increases gradually. With the increase of rotation frequency and atomic density–density interaction, the number of half-skyrmions on the three chains and in the regions between two chains increases gradually. The relationships of the total number of half-skyrmions on the three chains with the increase of SU(3) SOC strength, rotation frequency and atomic density–density interaction are also given. In addition, changing the anisotropic SU(3) SOC strength can regulate the number and morphology of the half-skyrmion chains.

Based on first-principles calculations, the unconventional Rashba- and Zeeman-type spin splitting can simultaneously coexist in the Pb-adsorbed monolayer WSe2 system. The first two adsorption configurations t 1 and t 2 show remarkable features under the spin–orbit coupling, in which two split energy branches show same spin states at the left or right side of Γ, and the spin polarization is reversed for both Rashba band branches. For the second adsorption configuration, an energy gap was observed near the unconventional spin polarization caused by the repelled Rashba bands for avoid crossing, and this gap can produce non-dissipative spin current by applying the voltage. The results for t 2 configuration with spin reversal show that the repel band gap and Rashba parameter can be effectively regulated within the biaxial strain range of −8% to 6%. By changing the adsorption distance d between Pb and the neighboring Se atom layer, the reduced d caused the transfer from Rashba-type to Zeeman-type spin splitting. This predicted adsorption system would be promising for spintronic applications.

In this paper, spin-orbit coupling induced photovoltaic effect of cold atoms has been studied in a three-trap system which is an two-dimensional extension of a two-trap system reported previously. It is proposed here that atom coherent length is one of the important influence to the resistance of this photovoltaic battery. Current properties of the system for different geometrical structures of the trapping potentials are discussed. Numerical results show extension in the number of traps could cause current increase directly. Quantum master equation at finite temperature is used to treat this opened system. This work may give a theoretical basis for further development of the photovoltaic effect of neutral atoms., 6 pages, 5 figures

In this work, the electrical and spin properties of monolayer MoSi2X4 (X= N, P, As, and Sb) under vertical strain are investigated. The band structures state that MoSi2N4 is an indirect semiconductor, whereas other compounds are direct semiconductors. The vertical strain has been selected to modify the electrical properties. The bandgap shows a maximum and decreases for both tensile and compressive strains. The valence band at K-point displays a large spin-splitting, whereas the conduction band has a negligible splitting. On the other hand, the second conduction band has a large spin-splitting and moves down under vertical strain which leads to a large spin-splitting in both conduction and valence bands edges. The projected density of states along with the projected band structure clarifies the origin of these large spin-splittings. These three spin-splittings can be controlled by vertical strain.

Quantum speed limit and entanglement of a two-spin Heisenberg XYZ system in an inhomogeneous external magnetic field are investigated. The physical system studied is the excess electron spin in two adjacent quantum dots. The influences of magnetic field inhomogeneity as well as spin–orbit coupling are studied. Moreover, the spin interaction with surrounding magnetic environment is investigated as a non-Markovian process. The spin–orbit interaction provides two important features: the formation of entanglement when two qubits are initially in a separated state and the degradation and rebirth of the entanglement.

The multi-reference configuration interaction method plus Davidson correction (MRCI+Q) are adopted to study the low-lying states of SH with consideration of scalar relativistic effect, core-valence (CV) electron correlation, and spin–orbit coupling (SOC) effect. The SOC effect on the low-lying states is considered by utilizing the full Breit–Pauli operator. The potential energy curves (PECs) of 10 Λ–S states and 18 Ω states are calculated. The dipole moments of 10 Λ–S states are calculated, and the variation along the internuclear distance is explained by the electronic configurations. With the help of calculated SO matrix elements, the possible predissociation channels of A2Σ+, c4Σ− and F2Σ− are discussed. The Franck–Condon factors of A2Σ+–X2Π, F2Σ−–X2Π and E2Σ+–X2Π transitions are determined, and the radiative lifetimes of A2Σ+ and F2Σ− states are evaluated, which are in good agreement with previous experimental results.

9 pags., 6 figs., We propose an experimental realization of the spin Hall effect in graphene by illuminating a graphene sheet on top of a substrate with circularly polarized monochromatic light. The substrate induces a controllable Rashba type spin-orbit coupling which breaks the spin-degeneracy of the Dirac cones but it is gapless. The circularly polarized light induces a gap in the spectrum and turns graphene into a Floquet topological insulator with spin dependent edge states. By analyzing the high and intermediate frequency regimes, we find that in both parameter limits, the spin-Chern number can be tuned by the effective coupling strength of the charge particles to the radiation field and determine the condition for the photoinduced topological phase transition., This work has been supported by CEDIA via the project CEPRA-XII-2018-06 Espectroscopía Mecánica: Transporte interacción materia radiación’. We also acknowledge financial support through Spanish grants PGC2018-094180-B-I00 (MCIU/AEI/FEDER, EU) and FIS2015-63770-P(MINECO/ FEDER, EU), CAM/FEDER Project No.S2018/TCS-4342 (QUITEMAD-CM) and CSIC Research Platform PTI-001.

The analysis of the impact of spin–orbit coupling (SOC) on the Kondo state has generated considerable controversy, mainly regarding the dependence of the Kondo temperature T K on SOC strength. Here, we study the one-dimensional (1D) single impurity Anderson model (SIAM) subjected to Rashba (α) and Dresselhaus (β) SOC. It is shown that, due to time-reversal symmetry, the hybridization function between impurity and quantum wire is diagonal and spin independent (as it is the case for the zero-SOC SIAM), thus the finite-SOC SIAM has a Kondo ground state similar to that for the zero-SOC SIAM. This similarity allows the use of the Haldane expression for T K, with parameters renormalized by SOC, which are calculated through a physically motivated change of basis. Analytic results for the parameters of the SOC-renormalized Haldane expression are obtained, facilitating the analysis of the SOC effect over T K. It is found that SOC acting in the quantum wire exponentially decreases T K while SOC at the impurity exponentially increases it. These analytical results are fully supported by calculations using the numerical renormalization group (NRG), applied to the wide-band regime, and the projector operator approach, applied to the infinite-U regime. Literature results, using quantum Monte Carlo, for a system with Fermi energy near the bottom of the band, are qualitatively reproduced, using NRG. In addition, it is shown that the 1D SOC SIAM for arbitrary α and β displays a persistent spin helix SU(2) symmetry similar to the one for a 2D Fermi sea with the restriction α = β. VL acknowledges a PhD scholarship from the Brazilian Agency Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), process 160071/2015-1, and financial support from the Generalitat Valenciana through Grant reference Prometeo 2017/139. MM acknowledges a PhD scholarship from the Brazilian Agency Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). GBM acknowledges financial support from CNPq, processes 424711/2018-4 and 305150/2017-0. EVA acknowledges financial support from CNPq, process 306000/2017-2.

A protocol for controlling the localization of an electron with a fixed projection of spin between two quantum dots in a material with spin-orbit (SO) interaction is studied. Due to SO coupling, the manipulation of the electron shuttling between both quantum dots also leads to a mixing between spin projections near to the avoided crossing of levels. We use a transitionless quantum driving approach, neglecting SO interaction, to analytically design simple electric and magnetic pulses able to rapidly drive the electron along an adiabatic Landau–Zener manifold. We show that the same fields in the presence of SO interaction can also give a fast high-fidelity transition between the qubit states. The performance of the proposed protocol is assessed in the presence of SO interactions of typical semiconductor materials. It is shown that it provides a fast and efficient spin-conserving method for controlling the electron position in a double quantum dot. Fil: Gomez, Sergio Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; Argentina Fil: Romero, Rodolfo Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; Argentina

A second-order perturbation (2PT) approach to the spin-orbit interaction (SOI) is implemented within a density-functional theory framework. Its performance is examined by applying it to the calculation of the magnetocrystalline anisotropy energies (MAE) of benchmark systems, and its efficiency and accuracy are compared with the popular force theorem method. The case studies are tetragonal FeMe alloys (Me=Co, Cu, Pd, Pt, Au), as well as FeMe (Me=Co, Pt) bilayers with (111) and (100) symmetry, which cover a wide range of SOI strength and electronic band structures. The 2PT approach is found to provide a very accurate description for 3d and 4d metals and, moreover, this methodology is robust enough to predict easy axis switching under doping conditions. In all cases, the details of the bandstructure, including states far from the Fermi level, are responsible for the finally observed MAE value, sometimes overruling the effect of the SOI strength. From a technical point of view, it is confirmed that accuracy in the MAE calculations is subject to the accuracy of the Fermi level determination., Discussions with G Teobaldi and M dos Santos Dias are acknowledged. MB-R and AA thank financial support from MINECO (grant number FIS2016-75862-P), the University of the Basque Country (UPV/EHU) and the Basque Government (IT-756-13). JIC thanks MINECO for grant MAT2015-66888-C3-1R. Computational resources were provided by the DIPC computing centre.

We investigate the spin-Hall conductivity (SHC) in the two-dimensional spin–orbit coupled systems by taking spin precession into account. The influence of spin precession on the spin-Hall current in the presence of disorder is investigated. Perturbation method leads to the result that the spin dynamics is composed of Larmor (periodic) and non-Larmor (non-periodic) precession. The non-Larmor component of spin is found to be the same result obtained from the Kubo formula in the short time limit. The Larmor component of spin, i.e., spin precession in the unperturbed system, was neglected in the previous studies, but it plays an important role in the linear response theory. The Larmor precession of spin should be zero after time average over several complete periods because there is no specific orientation perpendicular to the plane. By using the requirement of vanishing time-averaged Larmor precession of spin, we calculate the time-averaged non-Larmor SHC for k-cubic Rashba system by using the conventional definition of the spin current. Our result is 2.1(q/8π) which is very close to the experimental value 2.2(q/8π) by Wunderlich et al [2005 Phys. Rev. Lett. 94, 047204], where −q is the electric charge.

We introduce a generalized Rashba coupling approximation to analytically solve confined two-dimensional electron systems with both the Rashba and Dresselhaus spin–orbit couplings in an external magnetic field. A solvable Hamiltonian is obtained by performing a simple change of basis, which has the same form as that with only Rashba coupling. Each Landau state becomes a new displaced-Fock state instead of the original Harmonic oscillator Fock state. Analytical energies are consistent with the numerical ones in a wide range of coupling strength even for a strong Zeeman splitting, exhibiting the validity of the analytical approximation. By using the eigenstates, spin polarization correctly displays a jump at the energy-level crossing point, where the corresponding spin conductance exhibits a pronounced resonant peak. As the component of the Dresselhaus coupling increases, the resonant point shifts to a smaller value of the magnetic field. In contrast to pure Rashba couplings, we find that the Dresselhaus coupling and Zeeman splittings tend to suppress the resonant spin Hall effect. Our method provides an easy-to-implement analytical treatment to two-dimensional electron gas systems with both types of spin–orbit couplings by applying a magnetic field.

The current in response to a bias in certain two-dimensional electron gas (2DEG), can have a nonzero transverse component under a finite magnetic field applied in the plane where electrons are confined. This phenomenon known as planar Hall effect is accompanied by dependencies of both the longitudinal and the transverse components of the current on the angle $\phi$ between the bias direction and the magnetic field. In 2DEG with spin orbit coupling (SOC) such as oxide interfaces, this effect has been experimentally witnessed. Further, a fourfold oscillation in longitudinal resistance as a function of $\phi$ has also been observed. Motivated by these, we perform scattering theory calculations on a 2DEG with SOC in presence of an in-plane magnetic field connected to two dimensional leads on either sides to obtain longitudinal and transverse conductances. We find that the longitudinal conductance is $\pi$-periodic and the transverse conductance is $2\pi$-periodic in $\phi$. The magnitude of oscillation in transverse conductance with $\phi$ is enhanced in certain patches in $(\alpha,b)$-plane where $\alpha$ is the strength of SOC and $b$ is Zeeman energy due to magnetic field. The oscillation in transverse conductance with $\phi$ can be highly multi-fold for large values of $\alpha$ and $b$. The highly multi-fold oscillations of transverse conductance are due to Fabry-P\'erot type interference between the modes in the central region as backed by its length dependent features. Our study establishes that SOC in a material is sufficient to observe planar Hall effect without the need for anisotropic magnetic ordering or nontrivial topology of the bandstructure., Comment: 6 pages, 7 captioned figures

We theoretically study a controllable spatial spin converter and spin valve by using a Y-shaped even-chain zigzag graphene nanoribbon (ZGR) junction with Rashba spin orbit coupling (SOC) and strain. By calculating the spin-dependent conductance spectra of different tunneling terminals through the multi-terminal Landauer formula, we find that the spin up electron can flip its spin orientation, and convert to spin down one on the left electrode, the same spin converting phenomena can be inhibited on the right terminal. The above spin flipping and its valve phenomena are derived from the interactions of the Rashba SOC, strain and magnetization layout. When the strain's orientation is along (perpendicular) to the zigzag chain's direction, the valley valve effect of the even-chain ZGR is remained, the Rashba SOC takes little effect on the spatial spin switching, one can get 100% polarized spin up (down) electrons at different terminals of the Y-shaped ZGR due to the valley valve effect. When the strain is changed to other direction, the valley valve effect is partly destroyed, Rashba SOC can enhance the spin flipping conductance and break the ON/OFF transport states of spin valve. Our investigations might be useful in designing a multi-parameter controllable spin valve and spin detector based on a multi-terminal graphene nanoribbon junction.

Topological nodal line (TNL) materials with one-dimensional band-crossing points (BCPs) exhibit interesting electronic characteristics and have special applications in electronic devices. Normally, based on the slopes of the crossing bands, the BCPs can be divided into two types, i.e., type I and type II nodal points. Based on the combination of the different types of nodal points, the nodal lines (NLs) can be divided into three categories: (i) type I NL, type II NL, and hybrid NL, these being formed by type I nodal points, type II nodal points, and type I and II nodal points, respectively. Compared with the large number of predicted type I NL materials, there are less type II and hybrid NL materials. In this study, it is predicted that P63/mmc type TiSe metal is a topological material which exhibits all types of NL states. Furthermore, the dynamic stability as well as the effect of spin–orbit coupling on the topological signatures are examined. Also, the nontrivial surface states are shown to provide evidence for the occurrence of the NL states. This novel material can be seen as a good platform to use for further investigations on the three types of NLs and diverse fermions.

Light–matter interaction at dielectric interfaces usually manifests as spin-dependent correction to light propagation, known as classical Imbert–Fedorov (IF) shift or photonic spin Hall effect, ruled by the general spin–orbit interaction (SOI) of light. Even though vector wave equations and strong SOI-based perturbation theory in a wave picture can offer good solutions to describe the modal dispersion in optical fibers, it is difficult for all these to provide an intuitive insight into the walking off for twisted (or vortex) light beams carrying orbital angular momentum (OAM). Here we present a new perspective to the topologically spin-dependent modal splitting for the twisted light highly confined in optical fibers based on the classical IF shift on geometric optics. We verify this topologically IF-shift-based walking off by comparing the analytical results of modal splitting degrees with the solutions of eigen equation, and associate the longitudinal projection of IF shift with an interesting resonance of fiber Bragg gratings locked by the signs of SAM or OAM. This interpretation provides an insight supplement to describe light ray propagating in optical fibers together with both longitudinal Goos–Hänchen and transverse IF shift under the total internal reflection, and may benefit the development of nanoscale fiber-based light on optically classical or quantum communication and metrology.

We show that interfacial spin–orbit coupling is an efficient source of spin-orbit torques in a Co/Pt bilayer, a prototypical spin-orbitronic device. We find that the spin–orbit coupling at the Co/Pt interface can be effectively manipulated by inserting a thin TiN layer. We show that the strong spin–orbit coupling at the Co/Pt interface enables efficient generation of interfacial spin-orbit torques, as well as suppresses bulk spin-orbit torques, resulting in the dominance of the interfacial contribution in the generation of the spin-orbit torques. This result provides an important information for developing efficient spin-orbitronic devices based on the interfacial spin–orbit coupling.

We study the polaron problem of an impurity immersed in a dissipative spin-orbit coupled Fermi gas via a non-self-consistent T -matrix method. We first propose an experimental scheme to realize a spin-orbit coupled Fermi bath with dissipation, and show that such a system can be described by a non-Hermitian Hamiltonian that contains an imaginary spin-flip term and an imaginary constant shift term. We find that the non-Hermiticity will change the single-particle dispersion of the bath gas, and modify the properties of attractive and repulsive polarons such as energy, quasi-particle residue, effective mass, and decay rate. We also investigate the Thouless criteria corresponding to the instability of the polaron-molecule transition, which suggests a molecule state is more facilitated with stronger bath dissipation. Finally, we consider the case with finite impurity density and calculate the interaction between polarons. Our result extends the study of polaron physics to non-Hermitian systems and may be realized in future experiments.

We study the properties of Bose–Einstein condensates under a non-Hermitian spin–orbit coupling (SOC), induced by a dissipative two-photon Raman process. We focus on the dynamics of the condensate at short times, when the impact of decoherence induced by quantum jumps is negligible and the dynamics is coherently driven by a non-Hermitian Hamiltonian. Given the significantly modified single-particle physics by dissipative SOC, the interplay of non-Hermiticity and interaction leads to a quasi-steady-state phase diagram different from its Hermitian counterpart. In particular, we find that dissipation can induce a phase transition from the stripe phase to the plane-wave phase. We further map out the phase diagram with respect to the dissipation and interaction strengths, and finally investigate the stability of quasi-steady states through the time-dependent dissipative Gross–Pitaevskii equation. Our results are readily accessible based on standard experiments with synthetic spin–orbit couplings.

Applying an electric field perpendicular to the axis of a silicene armchair nanotube allows us to numerically study the formation of eight topological edge states as silicene’s intrinsic spin–orbit gap is closed by the sublattice-staggered electrostatic potential created by the electric field. Following their evolution with electric field, it is revealed that, at very small fields, these eight states are very broad, spin-locked, and sublattice constrained, inheriting their properties from the K and K′ states in a silicene two-dimensional honeycomb lattice. Four of those states are centered at the very top of the nanotube and the other four states are centered at the very bottom. As the field increases, each state starts to become narrower and to spread its spectral weight to the other sublattice. With further increase of the field, each state starts to spatially split, while the sublattice spreading continues. Once the spectral weight of each state is distributed evenly among both sublattices, the state has also effectively split into two spatially disconnected parts, after which, further increasing of the field will spread apart the two halves, moving them to the lateral regions of the nanotube, at the same time that the state halves become narrower. This is consistent with the formation of topological edge states, which delimit four ribbon-like topologically different regions: top and bottom topologically trivial ‘ribbons’ (where the electric field has induced a topological phase transition) that are adjacent to two topologically nontrivial ‘ribbons’ located at opposing sides of the nanotube. We also briefly access the possibility of observing these edge states by calculating the electronic properties for an electric field configuration that can be more readily produced in the laboratory.

There is rapidly expanding interest in exploiting the spin of valence-band holes rather than conduction-band electrons for spin qubit semiconductor circuits composed of coupled quantum dots. The hole platform offers stronger spin–orbit interaction (SOI), large difference between in-dot-plane and out-of-dot-planeg-factors, i.e.g-factor anisotropy, and a significantly reduced hyperfine coupling to nuclei in the host material. These attributes collectively can deliver fast all-electric coherent spin manipulation, efficient spin-flip inter-dot tunneling channels, a voltage tunable effectiveg-factor, ag-factor adjustable to nearly zero in an appropriately oriented external magnetic field, and long spin relaxation and coherence times. Here, we review our recent work on the physics of heavy holes confined in a planar GaAs/AlGaAs double quantum dot system with strong SOI. For asingle-hole, we have performed resonant tunneling magneto-spectroscopy to extract spin-flip and spin-conserving tunneling strengths, implemented spin-flip Landau–Zener–Stückelberg–Majorana (LZSM) interferometry, determined the spin relaxation timeT1as a function of magnetic field using a fast single-shot latched charge technique, electrically tuned the effectiveg-factor revealed by electric dipole spin resonance, and found signatures of the hyperfine interaction and dynamic nuclear polarization with holes. Fortwo-holes, we have measured the energy spectrum in the presence of strong SOI (and so not limited by Pauli spin blockade), quantified the heavy-hole (HH)g-factor anisotropy on tilting the magnetic field, described a scheme to employ HHs whoseg-factor is tunable to nearly zero for an in-plane magnetic field for a coherent photon-to-spin interface, and observed a well-defined LZSM interference pattern at small magnetic fields on pulsing through the singlet-triplet anti-crossing.

Recent experimental observations of spin–orbit coupling (SOC) in Bose–Einstein condensates (BECs) open the way for investigating novel physics of nonlinear waves with promising applications in atomic physics and condensed matter physics. The interplay between atomic interactions and SOC are crucial for the understanding of the dynamics of nonlinear waves in BECs with SOC. Here, in the small linear coupling regime, an approach is presented which allows us to derive an infinite number of novel approximate solutions of the Gross–Pitaevskii equations (GPEs) in one and two dimensions including SOCs, time-dependent external potentials, and nonlinearities leading to breathers and periodic as well as quasiperiodic nonlinear waves. To verify the theoretical predictions we perform numerical simulations which show for several cases a very good agreement with the analytics. For the case of one spatial dimension, it is shown that functions describing the external potential and nonlinearities cannot be chosen independently. The management of the solutions is clarified along with some important physical properties such as Josephson oscillations and Rosen–Zener oscillations.

Valley filter is a promising device for producing valley polarized current in graphene-like two-dimensional honeycomb lattice materials. The relatively large spin–orbit coupling in silicene contributes to remarkable quantum spin Hall effect, which leads to distinctive valley-dependent transport properties compared with intrinsic graphene. In this paper, quantized conductance and valley polarization in silicene nanoconstrictions are theoretically investigated in quantum spin-Hall insulator phase. Nearly perfect valley filter effect is found by aligning the gate voltage in the central constriction region. However, the valley polarization plateaus are shifted with the increase of spin–orbit coupling strength, accompanied by smooth variation of polarization reversal. Our findings provide new strategies to control the valley polarization in valleytronic devices.

Graphene is an excellent two-dimensional materials with high-mobility and relativistic electronic linear dispersion. Its rich physical properties such as half-integer quantum Hall effect and device application potential have been continuously attracting great attention. However, light carbon atoms also imply negligible intrinsic spin–orbit coupling (SOC) strength which hinders its spintronic application. To enhance the SOC effect, we introduce a special deformation vector with chiral curvature, borrowed from the Einstein theory of general relativity, to mimic space warping and twisting. The derived Rashba type pseudospin–spin coupling locks the spin orientation of an electron with respect to its pseudospin. Combined with the original Dirac type Hamiltonian specifying the pseudospin orientation of an electron with respect to its wavevector, it lifts the spin degeneracy and paves the way for graphene-based spintronic devices. An estimate suggests that a Rashba type pseudospin–spin coupling of the order of 5 meV can be achieved in tens nanometer samples.

We investigate the ground states of spin-1 Bose–Einstein condensates (BECs) with spin–orbit coupling in a radially periodic potential by numerically solving the coupled Gross–Pitaevskii equations. In the radially periodic potential, we first demonstrate that spin–orbit-coupled antiferromagnetic BECs support a multiring petal phase. Polar–core vortex can be observed from phase profiles, which is manifested as circularly symmetric distribution. We further show that spin–orbit coupling can induce multiring soliton structure in ferromagnetic BECs. It is confirmed especially that the wave-function phase of the ring corresponding to uniform distribution satisfies the rotational symmetry, and the wave-function phase of the ring corresponding to partial splitting breaks the rotational symmetry. Adjusting the spin–orbit coupling strength can control the number of petal in antiferromagnetic BECs and the winding numbers of wave-function in ferromagnetic BECs. Finally, we discuss effects of spin-independent and spin-dependent interactions on the ground states.

We study the propagation of light in twisted anisotropic fibers by obtaining the analytical expressions and propagation constants for higher-order modes with the azimuthal number | ℓ | > 1 . It is shown that for arbitrary fiber parameters, the modes are elliptically polarized optical vortices of well-defined orbital angular momentum. We reveal the phenomena of orbital birefringence and the optical Zeeman effect for the higher-order topologically charged fiber modes. Finally, circularly and linearly polarized optical vortices are demonstrated to be modes that are robust against small constant and spatially varying perturbations of both fiber material and form anisotropy; this robustness is due to the effects of the spin–orbit interaction and/or torsional-stress-induced orbital birefringence.

We study the Bloch oscillation (BO) dynamics of spin–orbit coupled cold atoms in a one-dimensional Su–Schrieffer–Heeger optical lattice. The Hamiltonian of our system can be mapped into a tilted SSH ladder pierced by an effective magnetic flux. Based on the calculation of Wannier–Stark states, we investigate dynamical properties of BOs with the chiral character of spin-momentum locking. Importantly, the chiral Bloch–Zener oscillations can be induced by adjusting system parameters. The corresponding Landau–Zener (LZ) tunneling probability is analytically derived by the LZ model and we found a good agreement with the numerical simulation.

Spin–orbit coupling (SOC) links the spin degree of freedom to the orbital motion of electrons in a solid and plays an important role in the emergence of new physical phenomena. In non-centrosymmetric materials, the SOC locks the electron’s spin direction to its momentum resulting in non-trivial spin textures in the reciprocal space. Depending on the crystal symmetry, the spin texture may exhibit Rashba, Dresselhaus, persistent, or more intricate configurations. In ferroelectric materials these spin textures are coupled to the ferroelectric polarization and thus can be controlled by its orientation and magnitude. This provides a promising platform to explore the coupling between spin, orbital, valley, and lattice degrees of freedoms in solids and opens a new direction for nonvolatile spintronic devices, such as a spin-field-effect transistor and a valley spin valve. Here, we review the recent advances in spin-texture physics of ferroelectric materials and outline possible device implications.

Spin–orbit interaction of light serves as an important property of light, which deals with the study of polarization and phase modulations in the light beam. These studies are essential and principal characeristics of light beam that have been used for most of the nanophotonics applications. Silver nanoparticles (Ag NPs) prepared via biosynthesis are used for one of such nanophotonics application in scattering via studying the light scattered through these nanoparticles. The silver nanoparticles Ag NPs were synthesized using green method, where reduction of silver ions to silver nanoparticles happen during the reaction of aqueous solution of Ag NO3 with the biomolecules present in fresh leaf extract of Coleus amboinicus plant. The nanoparticles were characterized using UV-visible (UV–vis) spectroscopy, Transmission electron microscopy (TEM) and Fourier Transform Infrared (FTIR) spectroscopy. TEM analysis shows the wide size distribution of spherical shape nanoparticles with 80 nm average size. The study of polarization and phase changes in the scattered light field has been carried out using Stokes polarimetry in forward direction scattering. Under the preliminary measurements of Polarimetry, the modification in the polarization components was studied by demonstrating changes in the Stokes S2, S3 parameters, polarization orientation (ψ) and ellipticity angle (χ) using transverse magnetic (TM) polarized Gaussian light beam.