Besides equilibrium behavior,exploring the spin–phonon coupling in multiferroic materials under non-equilibrium conditions is crucial for a deep understanding of the mechanisms as well as their high-frequency applica...Besides equilibrium behavior,exploring the spin–phonon coupling in multiferroic materials under non-equilibrium conditions is crucial for a deep understanding of the mechanisms as well as their high-frequency applications.Here,by utilizing time-resolved refectance spectroscopy,we demonstrate ultrafast spin–phonon coupling dynamics in multiferroic 0.58BiFeO_(3)-0.42Bi_(0.5)K_(0.5)TiO_(3)(BF-BKT)single crystals.With ultrafast laser pumping,coherent acoustic phonons with low damping are created in BF-BKT.Temperature-dependent results indicate that both the frequency and amplitude of laser-induced coherent phonons are sensitive to the emergence of antiferromagnetic order.Moreover,the spin state change driven by external magnetic felds can enhance the oscillation amplitude of the coherent acoustic phonons even above the magnetic Néel temperature.These fndings experimentally confrm that spin–phonon coupling in multiferroic materials exists not only in the spin-ordered state but also in the spin-disordered state,and not only in the equilibrium state but also in the non-equilibrium state excited by ultrafast lasers,suggesting their promising applications in high-frequency devices.展开更多
With an extended Su–Schrieffer–Heeger model and Green's function method, the spin–orbit coupling(SOC) effects on spin admixture of electronic states and quantum transport in organic devices are investigated. Th...With an extended Su–Schrieffer–Heeger model and Green's function method, the spin–orbit coupling(SOC) effects on spin admixture of electronic states and quantum transport in organic devices are investigated. The role of lattice distortion induced by the strong electron–lattice interaction in organics is clarified in contrast with a uniform chain. The results demonstrate an enhanced SOC effect on the spin admixture of frontier eigenstates by the lattice distortion at a larger SOC,which is explained by the perturbation theory. The quantum transport under the SOC is calculated for both nonmagnetic and ferromagnetic electrodes. A more notable SOC effect on total transmission and current is observed for ferromagnetic electrodes, where spin filtering induced by spin-flipped transmission and suppression of magnetoresistance are obtained.Unlike the spin admixture, a stronger SOC effect on transmission exists for the uniform chain rather than the organic lattices with distortion. The reason is attributed to the modified spin-polarized conducting states in the electrodes by lattice configuration, and hence the spin-flip transmission, instead of the spin admixture of eigenstates. This work is helpful to understand the SOC effect in organic spin valves in the presence of lattice distortion.展开更多
Understanding the photoexcitation induced spin dynamics in ferromagnetic metals is important for the design of photo-controlled ultrafast spintronic device.In this work,by the ab initio nonadiabatic molecular dynamics...Understanding the photoexcitation induced spin dynamics in ferromagnetic metals is important for the design of photo-controlled ultrafast spintronic device.In this work,by the ab initio nonadiabatic molecular dynamics simulation,we have studied the spin dynamics induced by spin–orbit coupling(SOC)in Co and Fe using both spin-diabatic and spin-adiabatic representations.In Co system,it is found that the Fermi surface(E_(F))is predominantly contributed by the spin-minority states.The SOC induced spin flip will occur for the photo-excited spin-majority electrons as they relax to the E_(F),and the spin-minority electrons tend to relax to the EFwith the same spin through the electron–phonon coupling(EPC).The reduction of spin-majority electrons and the increase of spin-minority electrons lead to demagnetization of Co within100 fs.By contrast,in Fe system,the E_(F) is dominated by the spin-majority states.In this case,the SOC induced spin flip occurs for the photo-excited spin-minority electrons,which leads to a magnetization enhancement.If we move the E_(F) of Fe to higher energy by 0.6eV,the E_(F) will be contributed by the spin-minority states and the demagnetization will be observed again.This work provides a new perspective for understanding the SOC induced spin dynamics mechanism in magnetic metal systems.展开更多
By numerical propagation of the coupled Gross–Pitaevskii equations, the ground state phase of a SU(3) spin–orbit coupled Bose gas with nonlocal soft-core interactions has been investigated within the all parameter s...By numerical propagation of the coupled Gross–Pitaevskii equations, the ground state phase of a SU(3) spin–orbit coupled Bose gas with nonlocal soft-core interactions has been investigated within the all parameter space, showing strong dependence on the strength of SU(3) spin–orbit coupling, nonlocal soft-core interactions, spin-exchange interactions and Rydberg blockade radius. More specially, we also perform a detailed study of the dependence of soft-core interaction on the Rydberg blockade radius at the point of rotational symmetry breaking. Our results show that under the combined effects of such parameters, the ground state shows a threefold-degenerate magnetized state for ferromagnetic spin interaction, while a variety of lattice phases for antiferromagnetic spin interaction.展开更多
The various competing contributions to the anomalous Hall effect in spin-polarized two-dimensional electron gases in the presence of both intrinsic, extrinsic and external electric-field induced spin-orbit coupling we...The various competing contributions to the anomalous Hall effect in spin-polarized two-dimensional electron gases in the presence of both intrinsic, extrinsic and external electric-field induced spin-orbit coupling were investigated theoretically. Based on a unified semiclassical theoretical approach, it is shown that the total anomalous Hall conductivity can be expressed as the sum of three distinct contributions in the presence of these competing spin-orbit interactions, namely an intrinsic contribution determined by the Berry curvature in the momentum space, an extrinsic contribution determined by the modified Bloch band group velocity and an extrinsic contribution determined by spin-orbit-dependent impurity scattering. The characteristics of these competing contributions are discussed in detail in the paper.展开更多
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 electr...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 Cu_(2)TlX_(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 Cu_(2)TlSe_(2) to a semimetal in Cu_(2)TlTe_(2), 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.展开更多
Using a transfer matrix method, we investigate spin transport through a chain of polygonal rings with Dresselhaus spin-orbit coupling（DSOC）. The spin conductance is dependent on the number of sides in the polygons. ...Using a transfer matrix method, we investigate spin transport through a chain of polygonal rings with Dresselhaus spin-orbit coupling（DSOC）. The spin conductance is dependent on the number of sides in the polygons. When DSOC is considered in a chain which also has Rashba spin-orbit coupling（RSOC） of the same magnitude, the total conductance is the same as that for the same chain with no SOC. However, when the two types of SOC have different values, there results a unique anisotropic conductance.展开更多
We investigate the effect of Rashba spin-orbit coupling(RSOC)on photoconductivities of rectified currents in monolayer graphene with exchange field and sublattice potential.The system shows that the photoconductivitie...We investigate the effect of Rashba spin-orbit coupling(RSOC)on photoconductivities of rectified currents in monolayer graphene with exchange field and sublattice potential.The system shows that the photoconductivities of resonant shift and injection current contributions are nonzero,while the photoconductivities of non-resonant shift current contribution are zero.We find that the RSOC induces a warping term,which leads to the nonzero rectified currents.Moreover,the photoconductivities of resonant injection(shift)current contribution are(not)related to the relaxation rate.The similar behavior can be found in other Dirac materials,and our findings provide a way to tune the nonlinear transport properties of Dirac materials.展开更多
We study theoretically the influence of spin-orbit coupling induced by in-plane external electric field on the intrinsic spin-Hall effect in a two-dimensional electron gas with Rashba spin-orbit coupling. We show that...We study theoretically the influence of spin-orbit coupling induced by in-plane external electric field on the intrinsic spin-Hall effect in a two-dimensional electron gas with Rashba spin-orbit coupling. We show that, after such an influence is taken into account, the static intrinsic spin-Hall effect can be stabilized in a disordered Rashba twodimensional electron gas, and the static intrinsic spin-Hall conductivity shall exhibit some interesting characteristics as conceived in some original theoretical proposals.展开更多
The spin polarization phenomenon in lepton circular accelerators had been known for many years. It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orb...The spin polarization phenomenon in lepton circular accelerators had been known for many years. It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orbit coupling, such as spin resonances. We use numerical simulation to study the features of spin under the modulation of orbital motion in an electron storage ring. The various cases of depolarization due to spin-orbit coupling through an emitting photon and misalignment of magnets in the ring are discussed.展开更多
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 correlatio...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 10Λ–S states and 18?states are calculated.The dipole moments of 10Λ–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 A^(2)Σ+,c4Σ-and F^(2)Σ-are discussed.The Franck–Condon factors of A^(2)Σ^(+)–X^(2)Π,F^(2)Σ^(-)–X^(2)Πand E^(2)Σ^(+)–X^(2)Πtransitions are determined,and the radiative lifetimes of A^(2)Σ+and F^(2)Σ-states are evaluated,which are in good agreement with previous experimental results.展开更多
Within the frame of the Pavlov–Firsov spin–phonon coupling model, we study the spin-flip assisted by the acoustical phonon scattering between the first-excited state and the ground state in quantum dots. We analyze ...Within the frame of the Pavlov–Firsov spin–phonon coupling model, we study the spin-flip assisted by the acoustical phonon scattering between the first-excited state and the ground state in quantum dots. We analyze the behaviors of the spin relaxation rates as a function of an external magnetic field and lateral radius of quantum dot. The different trends of the relaxation rates depending on the magnetic field and lateral radius are obtained, which may serve as a channel to distinguish the relaxation processes and thus control the spin state effectively.展开更多
We study theoretically Josephson effect in a planar ballistic junction between two triplet superconductors with pwave orbital symmetries and separated by a two-dimensional(2D)semiconductor channel with strong Rashba s...We study theoretically Josephson effect in a planar ballistic junction between two triplet superconductors with pwave orbital symmetries and separated by a two-dimensional(2D)semiconductor channel with strong Rashba spin–orbit coupling.In triplet superconductors,three types of orbital symmetries are considered.We use Bogoliubov–de Gennes formalism to describe quasiparticle propagations through the junction and the supercurrents are calculated in terms of Andreev reflection coefficients.The features of the variation of the supercurrents with the change of the strength of Rashba spin–orbit coupling are investigated in some detail.It is found that for the three types of orbital symmetries considered,both the magnitudes of supercurrent and the current-phase relations can be manipulated effectively by tuning the strength of Rashba spin–orbit coupling.The interplay of Rashba spin–orbit coupling and Zeeman magnetic field on supercurrent is also investigated in some detail.展开更多
We study the ground-state phases of two-dimensional rotating spin-orbit coupled spin-1/2 Bose-Einstein condensates(BECs) in a gradient magnetic field. The competition between gradient magnetic field, spin-orbit coupli...We study the ground-state phases of two-dimensional rotating spin-orbit coupled spin-1/2 Bose-Einstein condensates(BECs) in a gradient magnetic field. The competition between gradient magnetic field, spin-orbit coupling and rotation leads to a variety of ground-state phase structures. In the weakly rotation regime, as the increase of gradient magnetic field strength, the BECs experiences a phase transition from the unstable phase to the single vortex-line phase. The unstable phase presents the vortex lines structures along the off-diagonal direction. With magnetic field gradient strength increasing, the number of vortex lines changes accordingly. As the magnetic field gradient strength increases further, the single vortex-line phase with a single vortex line along the diagonal direction is formed. The phase diagram shows that the boundary between the two phases is linear with the relative repulsion λ?≥?1 and is nonlinear with λ?展开更多
Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electron...Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electronic states of the molecule have not been well studied. In this paper, high accurate ab initio calculations on the Cd F molecule have been performed at the multi-reference configuration interaction level including Davidson correction（MRCI ＋ Q）. Adiabatic potential energy curves（PECs） of the 14 low-lying Λ–S states correlating with the two lowest dissociation limits Cd（~1S_g） ＋ F（~2P_u） and Cd（~3P_u） ＋ F（~2P_u） have been constructed. For the bound Λ–S and ？ states, the dominant electronic configurations and spectroscopic constants are obtained,and the calculated spectroscopic constants of bound states are consistent with previous experimental results. The dipole moments（DMs） of 2 Σ＋ and 2Π are determined, and the spin–orbit（SO） matrix elements between each pair of X2Σ＋, 22Σ＋, 12Π, and 22Π are obtained. The results indicate that the sudden changes of DMs and SO matrix elements arise from the variation of the electronic configurations around the avoided crossing region. Moreover,the Franck–Condon factors（FCFs）, the transition dipole moments（TDMs）, and radiative lifetimes of low-lying states-the ground state X2Σ＋are determined. Finally, the transitional properties of 22Π–X2Σ＋and 22Σ＋–X2Σ＋are studied. Based on our computed spectroscopic information of Cd F, the feasibility and challenge for laser cooling of Cd F molecule are discussed.展开更多
This article presents illustrations of an extended model of the electron to visualize how it spins and radiates in the external magnetic field. A time-varying magnetic field B produces a rotational induced electric fi...This article presents illustrations of an extended model of the electron to visualize how it spins and radiates in the external magnetic field. A time-varying magnetic field B produces a rotational induced electric field E which rotates (spins) the electron about its axis. In time-constant magnetic field: the electron radiates the cyclotron radiation. In time-varying magnetic field: synchrotron radiation is generated. The couplings between spin, acceleration and radiation will be discussed.展开更多
The magnetic anisotropy manipulation in the Sm_(3)Fe_(5)O_(12)(SmIG)films and its effect on the interfacial spin coupling in the CoFe/SmIG heterostructures were studied carefully.By switching the orientation of the Gd...The magnetic anisotropy manipulation in the Sm_(3)Fe_(5)O_(12)(SmIG)films and its effect on the interfacial spin coupling in the CoFe/SmIG heterostructures were studied carefully.By switching the orientation of the Gd_(3)Ga_(5)O_(12)substrates from(111)to(001),the magnetic anisotropy of obtained SmIG films shifts from in-plane to out-of-plane.Similar results can also be obtained in the films on Gd_(3)Ga_(5)O_(12)substrates,which identifies the universality of such orientation-induced magnetic anisotropy switching.Additionally,the interfacial spin coupling and magnetic anisotropy switching effect on the spin wave in CoFe/SmIG magnetic heterojunctions have also been explored by utilizing the time-resolved magneto-optical Kerr effect technique.It is intriguing to find that both the frequency and effective damping factor of spin precession in CoFe/SmIG heterojunctions can be manipulated by the magnetic anisotropy switching of SmIG films.These findings not only provide a route for the perpendicular magnetic anisotropy acquisition but also give a further path for spin manipulation in magnetic films and heterojunctions.展开更多
Moirésystems have emerged as an ideal platform for exploring interaction effects and correlated states.However,most of the experimental systems are based on either triangular or honeycomb lattices.In this study,b...Moirésystems have emerged as an ideal platform for exploring interaction effects and correlated states.However,most of the experimental systems are based on either triangular or honeycomb lattices.In this study,based on the self-consistent Hartree–Fock calculation,we investigate the phase diagram of the kagomélattice in a recently discovered system with two degenerateΓvalley orbitals and strong spin–orbit coupling.By focusing on the filling factors of 1/2,1/3 and 2/3,we identify various symmetry-breaking states by adjusting the screening length and dielectric constant.At the half filling,we discover that the spin–orbit coupling induces Dzyaloshinskii–Moriya interaction and stabilizes a classical magnetic state with 120°ordering.Additionally,we observe a transition to a ferromagnetic state with out-of-plane ordering.In the case of 1/3 filling,the system is ferromagnetically ordered due to the lattice frustration.Furthermore,for 2/3 filling,the system exhibits a pinned droplet state and a 120°magnetic ordered state at weak and immediate coupling strengths,respectively.For the strong coupling case,when dealing with non-integer filling,the system is always charge ordered with sublattice polarization.Our study serves as a starting point for exploring the effects of correlation in moirékagomésystems.展开更多
Ising superconductivity, induced by the strong spin–orbit coupling(SOC) and inversion symmetry breaking, can lead to the in-plane upper critical field exceeding the Pauli limit and hold significant potential for adva...Ising superconductivity, induced by the strong spin–orbit coupling(SOC) and inversion symmetry breaking, can lead to the in-plane upper critical field exceeding the Pauli limit and hold significant potential for advancing the study of topological superconductivity. However, the enhancement of Ising superconductivity is still a challenging problem, important for engineering Majorana fermions and exploring topological quantum computing. In this study, we investigated the superconducting properties of a series of van der Waals NbSe_(2-x)Te_(x) nanosheets. The Ising superconductivity in NbSe_(2-x)Te_(x) nanosheets can be significantly enhanced by the substitution of Te, an element with strong SOC. The fitted in-plane upper critical field of Nb Se_(1.5)Te_(0.5) nanosheets at absolute zero temperature reaches up to 3.2 times the Pauli limit. Angular dependence of magnetoresistance measurements reveals a distinct two-fold rotational symmetry in the superconducting transition region, highlighting the role of strong SOC. In addition, the fitting results of the Berezinskii–Kosterlitz–Thouless(BKT) transition and the two-dimensional(2D) Tinkham formula provide strong evidence for 2D superconductivity. These findings offer new perspectives for the design and modulation of the Ising superconducting state and pave the way for their potential applications in topological superconductivity and quantum technologies.展开更多
In this paper, we investigate the Berry phase of two coupled arbitrary spins driven by a time-varying magnetic field where the Hamiltonian is explicitly tlme-dependent. Using a technique of time-dependent gauge transf...In this paper, we investigate the Berry phase of two coupled arbitrary spins driven by a time-varying magnetic field where the Hamiltonian is explicitly tlme-dependent. Using a technique of time-dependent gauge transform the Berry phase and time-evolution operator are found explicitly in the adiabatic approximation. The general solutions for arbitrary spins are applied to the spin-1/2 system as an example of explanation.展开更多
基金supported by the National Key R&D Program of China(Grant No.2021YFA1600200)the National Natural Science Foundation of China(Grant Nos.U2032218 and 12111530283)。
文摘Besides equilibrium behavior,exploring the spin–phonon coupling in multiferroic materials under non-equilibrium conditions is crucial for a deep understanding of the mechanisms as well as their high-frequency applications.Here,by utilizing time-resolved refectance spectroscopy,we demonstrate ultrafast spin–phonon coupling dynamics in multiferroic 0.58BiFeO_(3)-0.42Bi_(0.5)K_(0.5)TiO_(3)(BF-BKT)single crystals.With ultrafast laser pumping,coherent acoustic phonons with low damping are created in BF-BKT.Temperature-dependent results indicate that both the frequency and amplitude of laser-induced coherent phonons are sensitive to the emergence of antiferromagnetic order.Moreover,the spin state change driven by external magnetic felds can enhance the oscillation amplitude of the coherent acoustic phonons even above the magnetic Néel temperature.These fndings experimentally confrm that spin–phonon coupling in multiferroic materials exists not only in the spin-ordered state but also in the spin-disordered state,and not only in the equilibrium state but also in the non-equilibrium state excited by ultrafast lasers,suggesting their promising applications in high-frequency devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974215,21933002,and 12274264)。
文摘With an extended Su–Schrieffer–Heeger model and Green's function method, the spin–orbit coupling(SOC) effects on spin admixture of electronic states and quantum transport in organic devices are investigated. The role of lattice distortion induced by the strong electron–lattice interaction in organics is clarified in contrast with a uniform chain. The results demonstrate an enhanced SOC effect on the spin admixture of frontier eigenstates by the lattice distortion at a larger SOC,which is explained by the perturbation theory. The quantum transport under the SOC is calculated for both nonmagnetic and ferromagnetic electrodes. A more notable SOC effect on total transmission and current is observed for ferromagnetic electrodes, where spin filtering induced by spin-flipped transmission and suppression of magnetoresistance are obtained.Unlike the spin admixture, a stronger SOC effect on transmission exists for the uniform chain rather than the organic lattices with distortion. The reason is attributed to the modified spin-polarized conducting states in the electrodes by lattice configuration, and hence the spin-flip transmission, instead of the spin admixture of eigenstates. This work is helpful to understand the SOC effect in organic spin valves in the presence of lattice distortion.
基金support of Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0450101)the National Natural Science Foundation of China(Grant Nos.12125408 and 11974322)+1 种基金the Informatization Plan of Chinese Academy of Sciences(Grant No.CAS-WX2021SF-0105)the support of the National Natural Science Foundation of China(Grant No.12174363)。
文摘Understanding the photoexcitation induced spin dynamics in ferromagnetic metals is important for the design of photo-controlled ultrafast spintronic device.In this work,by the ab initio nonadiabatic molecular dynamics simulation,we have studied the spin dynamics induced by spin–orbit coupling(SOC)in Co and Fe using both spin-diabatic and spin-adiabatic representations.In Co system,it is found that the Fermi surface(E_(F))is predominantly contributed by the spin-minority states.The SOC induced spin flip will occur for the photo-excited spin-majority electrons as they relax to the E_(F),and the spin-minority electrons tend to relax to the EFwith the same spin through the electron–phonon coupling(EPC).The reduction of spin-majority electrons and the increase of spin-minority electrons lead to demagnetization of Co within100 fs.By contrast,in Fe system,the E_(F) is dominated by the spin-majority states.In this case,the SOC induced spin flip occurs for the photo-excited spin-minority electrons,which leads to a magnetization enhancement.If we move the E_(F) of Fe to higher energy by 0.6eV,the E_(F) will be contributed by the spin-minority states and the demagnetization will be observed again.This work provides a new perspective for understanding the SOC induced spin dynamics mechanism in magnetic metal systems.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12175129, 12475004, 12175027, and 12005125)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No. ZDBSLY7016)+3 种基金the Shaanxi Fundamental Science Research Project for Mathematics and Physics (Grant No. 22JSY034)the Key Research and Development Projects of Shaanxi Province, China (Grant No. 2024GX-YBXM-564)the Scientific Research Program Funded by Shaanxi Provincial Education Department (Grant No. 23JP020)the Youth Innovation Team of Shaanxi Universities。
文摘By numerical propagation of the coupled Gross–Pitaevskii equations, the ground state phase of a SU(3) spin–orbit coupled Bose gas with nonlocal soft-core interactions has been investigated within the all parameter space, showing strong dependence on the strength of SU(3) spin–orbit coupling, nonlocal soft-core interactions, spin-exchange interactions and Rydberg blockade radius. More specially, we also perform a detailed study of the dependence of soft-core interaction on the Rydberg blockade radius at the point of rotational symmetry breaking. Our results show that under the combined effects of such parameters, the ground state shows a threefold-degenerate magnetized state for ferromagnetic spin interaction, while a variety of lattice phases for antiferromagnetic spin interaction.
基金supported by the National Natural Science Foundation of China (Grant No.10874049)
文摘The various competing contributions to the anomalous Hall effect in spin-polarized two-dimensional electron gases in the presence of both intrinsic, extrinsic and external electric-field induced spin-orbit coupling were investigated theoretically. Based on a unified semiclassical theoretical approach, it is shown that the total anomalous Hall conductivity can be expressed as the sum of three distinct contributions in the presence of these competing spin-orbit interactions, namely an intrinsic contribution determined by the Berry curvature in the momentum space, an extrinsic contribution determined by the modified Bloch band group velocity and an extrinsic contribution determined by spin-orbit-dependent impurity scattering. The characteristics of these competing contributions are discussed in detail in the paper.
基金supported by the National Natural Science Foundation of China (Grant No. 11774190)。
文摘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 Cu_(2)TlX_(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 Cu_(2)TlSe_(2) to a semimetal in Cu_(2)TlTe_(2), 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.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61176089 and 11504083)the Foundation of Shijiazhuang University,China(Grant No.XJPT002)
文摘Using a transfer matrix method, we investigate spin transport through a chain of polygonal rings with Dresselhaus spin-orbit coupling（DSOC）. The spin conductance is dependent on the number of sides in the polygons. When DSOC is considered in a chain which also has Rashba spin-orbit coupling（RSOC） of the same magnitude, the total conductance is the same as that for the same chain with no SOC. However, when the two types of SOC have different values, there results a unique anisotropic conductance.
基金Project supported by the Shandong Province Natural Science Foundation(Grant No.ZR2021MF077)。
文摘We investigate the effect of Rashba spin-orbit coupling(RSOC)on photoconductivities of rectified currents in monolayer graphene with exchange field and sublattice potential.The system shows that the photoconductivities of resonant shift and injection current contributions are nonzero,while the photoconductivities of non-resonant shift current contribution are zero.We find that the RSOC induces a warping term,which leads to the nonzero rectified currents.Moreover,the photoconductivities of resonant injection(shift)current contribution are(not)related to the relaxation rate.The similar behavior can be found in other Dirac materials,and our findings provide a way to tune the nonlinear transport properties of Dirac materials.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10874049)the State Key Program for Basic Research of China (Grant No. 2007CB925204)the Natural Science Foundation of Guangdong Province of China (GrantNo. 07005834)
文摘We study theoretically the influence of spin-orbit coupling induced by in-plane external electric field on the intrinsic spin-Hall effect in a two-dimensional electron gas with Rashba spin-orbit coupling. We show that, after such an influence is taken into account, the static intrinsic spin-Hall effect can be stabilized in a disordered Rashba twodimensional electron gas, and the static intrinsic spin-Hall conductivity shall exhibit some interesting characteristics as conceived in some original theoretical proposals.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10875118)
文摘The spin polarization phenomenon in lepton circular accelerators had been known for many years. It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orbit coupling, such as spin resonances. We use numerical simulation to study the features of spin under the modulation of orbital motion in an electron storage ring. The various cases of depolarization due to spin-orbit coupling through an emitting photon and misalignment of magnets in the ring are discussed.
基金the National Natural Science Foundation of China(Grant No.11874177)the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province,China(Grant No.LBH-Q20189)+1 种基金the Natural Science Research Project of the Education Department of Anhui Province,China(Grant Nos.KJ2020A0544 and KJ2018A0335)the Excellent Youth Talent Project of the Education Department of Anhui Province,China(Grant No.gxyq ZD2019046)。
文摘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 10Λ–S states and 18?states are calculated.The dipole moments of 10Λ–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 A^(2)Σ+,c4Σ-and F^(2)Σ-are discussed.The Franck–Condon factors of A^(2)Σ^(+)–X^(2)Π,F^(2)Σ^(-)–X^(2)Πand E^(2)Σ^(+)–X^(2)Πtransitions are determined,and the radiative lifetimes of A^(2)Σ+and F^(2)Σ-states are evaluated,which are in good agreement with previous experimental results.
基金supported by the National Natural Science Foundation of China(Grant No.11264001)the Natural Science Foundation of Inner Mongolia,China(Grant No.2012MS0116)
文摘Within the frame of the Pavlov–Firsov spin–phonon coupling model, we study the spin-flip assisted by the acoustical phonon scattering between the first-excited state and the ground state in quantum dots. We analyze the behaviors of the spin relaxation rates as a function of an external magnetic field and lateral radius of quantum dot. The different trends of the relaxation rates depending on the magnetic field and lateral radius are obtained, which may serve as a channel to distinguish the relaxation processes and thus control the spin state effectively.
文摘We study theoretically Josephson effect in a planar ballistic junction between two triplet superconductors with pwave orbital symmetries and separated by a two-dimensional(2D)semiconductor channel with strong Rashba spin–orbit coupling.In triplet superconductors,three types of orbital symmetries are considered.We use Bogoliubov–de Gennes formalism to describe quasiparticle propagations through the junction and the supercurrents are calculated in terms of Andreev reflection coefficients.The features of the variation of the supercurrents with the change of the strength of Rashba spin–orbit coupling are investigated in some detail.It is found that for the three types of orbital symmetries considered,both the magnitudes of supercurrent and the current-phase relations can be manipulated effectively by tuning the strength of Rashba spin–orbit coupling.The interplay of Rashba spin–orbit coupling and Zeeman magnetic field on supercurrent is also investigated in some detail.
基金supported by the NSF of China under Grant No11 904 242the NSF of Hebei province under Grant No A2019210280。
文摘We study the ground-state phases of two-dimensional rotating spin-orbit coupled spin-1/2 Bose-Einstein condensates(BECs) in a gradient magnetic field. The competition between gradient magnetic field, spin-orbit coupling and rotation leads to a variety of ground-state phase structures. In the weakly rotation regime, as the increase of gradient magnetic field strength, the BECs experiences a phase transition from the unstable phase to the single vortex-line phase. The unstable phase presents the vortex lines structures along the off-diagonal direction. With magnetic field gradient strength increasing, the number of vortex lines changes accordingly. As the magnetic field gradient strength increases further, the single vortex-line phase with a single vortex line along the diagonal direction is formed. The phase diagram shows that the boundary between the two phases is linear with the relative repulsion λ?≥?1 and is nonlinear with λ?
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11604052,11404180,and 11574114)the Natural Science Foundation of Heilongjiang Province,China(Grant No.A2015010)+3 种基金the Natural Science Foundation of Anhui Province,China(Grant No.1608085MA10)the International Science&Technology Cooperation Program of Anhui Province,China(Grant No.1403062027)the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province,China(Grant No.2015095)the Natural Science Foundation of Jilin Province,China(Grant No.20150101003JC)
文摘Cd F molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the Cd F molecule, electronic states of the molecule have not been well studied. In this paper, high accurate ab initio calculations on the Cd F molecule have been performed at the multi-reference configuration interaction level including Davidson correction（MRCI ＋ Q）. Adiabatic potential energy curves（PECs） of the 14 low-lying Λ–S states correlating with the two lowest dissociation limits Cd（~1S_g） ＋ F（~2P_u） and Cd（~3P_u） ＋ F（~2P_u） have been constructed. For the bound Λ–S and ？ states, the dominant electronic configurations and spectroscopic constants are obtained,and the calculated spectroscopic constants of bound states are consistent with previous experimental results. The dipole moments（DMs） of 2 Σ＋ and 2Π are determined, and the spin–orbit（SO） matrix elements between each pair of X2Σ＋, 22Σ＋, 12Π, and 22Π are obtained. The results indicate that the sudden changes of DMs and SO matrix elements arise from the variation of the electronic configurations around the avoided crossing region. Moreover,the Franck–Condon factors（FCFs）, the transition dipole moments（TDMs）, and radiative lifetimes of low-lying states-the ground state X2Σ＋are determined. Finally, the transitional properties of 22Π–X2Σ＋and 22Σ＋–X2Σ＋are studied. Based on our computed spectroscopic information of Cd F, the feasibility and challenge for laser cooling of Cd F molecule are discussed.
文摘This article presents illustrations of an extended model of the electron to visualize how it spins and radiates in the external magnetic field. A time-varying magnetic field B produces a rotational induced electric field E which rotates (spins) the electron about its axis. In time-constant magnetic field: the electron radiates the cyclotron radiation. In time-varying magnetic field: synchrotron radiation is generated. The couplings between spin, acceleration and radiation will be discussed.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0303603 and 2016YFA0401803)the National Natural Science Foundation of China(Grant Nos.U2032218,11574316,11874120,61805256,and 11904367)+1 种基金the Plan for Major Provincial Science&Technology Project(Grant No.202003a05020018)the Key Research Program of Frontier Sciences,CAS(Grant No.QYZDB-SSW-SLH011)。
文摘The magnetic anisotropy manipulation in the Sm_(3)Fe_(5)O_(12)(SmIG)films and its effect on the interfacial spin coupling in the CoFe/SmIG heterostructures were studied carefully.By switching the orientation of the Gd_(3)Ga_(5)O_(12)substrates from(111)to(001),the magnetic anisotropy of obtained SmIG films shifts from in-plane to out-of-plane.Similar results can also be obtained in the films on Gd_(3)Ga_(5)O_(12)substrates,which identifies the universality of such orientation-induced magnetic anisotropy switching.Additionally,the interfacial spin coupling and magnetic anisotropy switching effect on the spin wave in CoFe/SmIG magnetic heterojunctions have also been explored by utilizing the time-resolved magneto-optical Kerr effect technique.It is intriguing to find that both the frequency and effective damping factor of spin precession in CoFe/SmIG heterojunctions can be manipulated by the magnetic anisotropy switching of SmIG films.These findings not only provide a route for the perpendicular magnetic anisotropy acquisition but also give a further path for spin manipulation in magnetic films and heterojunctions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12350404 and 12174066)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302600)+1 种基金the National Key Research and Development Program of China(Grant No.2019YFA0308404)the Science and Technology Commission of Shanghai Municipality(Grant Nos.23JC1400600 and 2019SHZDZX01)。
文摘Moirésystems have emerged as an ideal platform for exploring interaction effects and correlated states.However,most of the experimental systems are based on either triangular or honeycomb lattices.In this study,based on the self-consistent Hartree–Fock calculation,we investigate the phase diagram of the kagomélattice in a recently discovered system with two degenerateΓvalley orbitals and strong spin–orbit coupling.By focusing on the filling factors of 1/2,1/3 and 2/3,we identify various symmetry-breaking states by adjusting the screening length and dielectric constant.At the half filling,we discover that the spin–orbit coupling induces Dzyaloshinskii–Moriya interaction and stabilizes a classical magnetic state with 120°ordering.Additionally,we observe a transition to a ferromagnetic state with out-of-plane ordering.In the case of 1/3 filling,the system is ferromagnetically ordered due to the lattice frustration.Furthermore,for 2/3 filling,the system exhibits a pinned droplet state and a 120°magnetic ordered state at weak and immediate coupling strengths,respectively.For the strong coupling case,when dealing with non-integer filling,the system is always charge ordered with sublattice polarization.Our study serves as a starting point for exploring the effects of correlation in moirékagomésystems.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62488201 and 1240041502)the China Postdoctoral Science Foundation (Grant No. 2024T170990)+2 种基金the National Key R&D Program of China (Grant No. 2022YFA1204100)the Chinese Academy of Sciences (Grant No. XDB33030100)the Innovation Program of Quantum Science and Technology (Grant No. 2021ZD0302700)。
文摘Ising superconductivity, induced by the strong spin–orbit coupling(SOC) and inversion symmetry breaking, can lead to the in-plane upper critical field exceeding the Pauli limit and hold significant potential for advancing the study of topological superconductivity. However, the enhancement of Ising superconductivity is still a challenging problem, important for engineering Majorana fermions and exploring topological quantum computing. In this study, we investigated the superconducting properties of a series of van der Waals NbSe_(2-x)Te_(x) nanosheets. The Ising superconductivity in NbSe_(2-x)Te_(x) nanosheets can be significantly enhanced by the substitution of Te, an element with strong SOC. The fitted in-plane upper critical field of Nb Se_(1.5)Te_(0.5) nanosheets at absolute zero temperature reaches up to 3.2 times the Pauli limit. Angular dependence of magnetoresistance measurements reveals a distinct two-fold rotational symmetry in the superconducting transition region, highlighting the role of strong SOC. In addition, the fitting results of the Berezinskii–Kosterlitz–Thouless(BKT) transition and the two-dimensional(2D) Tinkham formula provide strong evidence for 2D superconductivity. These findings offer new perspectives for the design and modulation of the Ising superconducting state and pave the way for their potential applications in topological superconductivity and quantum technologies.
基金Project supported by the National Natural Science Foundation of China （Grant No 10475053）
文摘In this paper, we investigate the Berry phase of two coupled arbitrary spins driven by a time-varying magnetic field where the Hamiltonian is explicitly tlme-dependent. Using a technique of time-dependent gauge transform the Berry phase and time-evolution operator are found explicitly in the adiabatic approximation. The general solutions for arbitrary spins are applied to the spin-1/2 system as an example of explanation.
