We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate...We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate that the efficiency of the spin-orbit torque increases nearly linearly with the repetition number n,which is in excellent agreement with the spin Hall effect of the Pt_(0.75)Ti_(0.25)being essentially the only source of the observed spin-orbit torque.The perpendicular magnetic anisotropy field is also substantially enhanced by more than a factor of 2 as n increases from 1 to6.The[Pt_(0.75)Ti_(0.25)/Co-Ni multilayers/Ta]_n superlattice additionally exhibits deterministic,low-current-density magnetization switching despite the very large total layer thicknesses.The unique combination of strong spin-orbit torque,robust perpendicular magnetic anisotropy,low-current-density switching,and excellent high thermal stability makes the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice a highly compelling material candidate for ultrafast,energy-efficient,and long-data-retention spintronic technologies.展开更多
Spin-orbit coupling(SOC)plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved.Here,the prototypical perovskite iridate oxide SrIrO_(3)is inv...Spin-orbit coupling(SOC)plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved.Here,the prototypical perovskite iridate oxide SrIrO_(3)is investigated to gain more insights into the SOC effect in the modification of electronic structure and corresponding magnetic and electrical properties.The high pressure metastable orthorhombic SrIrO_(3)is successfully stabilized by physical and chemical pressures,in which the chemical pressure is induced by Ru doping in Ir site and Mg substitution of Sr position.Detailed structural,magnetic,electrical characterizations and density functional theory(DFT)calculations reveal that the substitution of Ru for Ir renders an enhanced metallic characteristic,while the introduction of Mg into Sr site results in an insulating state with 10.1%negative magnetoresistance at 10 K under 7 T.Theoretical calculations indicate that Ru doping can weaken the SOC effect,leading to the decrease of orbital energy difference between J_(1/2)and J_(3/2),which is favorable for electron transport.On the contrary,Mg doping can enhance the SOC effect,inducing a metal-insulator-transition(MIT).The electronic phase transition is further revealed by DFT calculations,confirming that the strong SOC and electron-electron interactions can lead to the emergence of insulating state.These findings underline the intricate correlations between lattice degrees of freedom and SOC in determining the ground state,which effectively stimulate the physical pressure between like structures by chemical compression.展开更多
Ferrimagnets are important for next-generation high-density ultrafast spintronic device applications.Magnetization compensation temperature(TM)is a fundamentally critical magnetic parameter for ferrimagnets besides th...Ferrimagnets are important for next-generation high-density ultrafast spintronic device applications.Magnetization compensation temperature(TM)is a fundamentally critical magnetic parameter for ferrimagnets besides their Curie temperature.Around TM,the spin-orbit switching efficiencies are extraordinarily high.Therefore,the accurate manipulation of TM from the material fabrication process is essential for the electrical steering of ferrimagnetic spins.In this work,CoTb thin films,with the 3 d and 4 f magnetic sublattices antiferromagnetically coupled to each other,are deposited at different temperatures.The magnetotransport and magnetic properties of these films are systematically investigated.It was found that the TM of this rare-earth ferrimagnet largely depends on the growth temperature and it can be tuned by over 100 K.Accordingly,the spins of an optimized ferrimagnetic CoTb thin film with its TM close to room temperature can be efficiently switched by the current-pulse-induced spin-orbit torque.Moreover,an artificial neural network utilizing the spin-orbit torque device was constructed,demonstrating an image recognition accuracy of approximately 92.5%,which is comparable to that of conventional software solutions.Thus,this work demonstrates the large tunability of TM of a rare earth ferrimagnet by chemical ordering and the great potential of such a ferrimagnet for electrically operated spintronic devices.展开更多
We study the trimer state in a three-body system,where two of the atoms are subject to Rashba-type spin-orbit coupling and spin-dependent loss while interacting spin-selectively with the third atom.The short-time cond...We study the trimer state in a three-body system,where two of the atoms are subject to Rashba-type spin-orbit coupling and spin-dependent loss while interacting spin-selectively with the third atom.The short-time conditional dynamics of the three-body system is effectively governed by a non-Hermitian Hamiltonian with an imaginary Zeeman field.Remarkably,the interplay of non-Hermitian single particle dispersion and the spin-selective interaction results in a Borromean state and an enlarged trimer phase.The stability of trimer state can be reflected by the imaginary part of trimer energy and the momentum distribution of trimer wave function.We also show the phase diagram of the three-body system under both real and imaginary Zeeman fields.Our results illustrate the interesting consequence of non-Hermitian spectral symmetry on the few-body level,which may be readily observable in current cold-atom experiments.展开更多
Spin-orbit interaction(SOI)can be introduced by the proximity effect to modulate the electronic properties of graphene-based heterostructures.In this work,we stack trilayer WSe_(2) on Bernal tetralayer graphene to inv...Spin-orbit interaction(SOI)can be introduced by the proximity effect to modulate the electronic properties of graphene-based heterostructures.In this work,we stack trilayer WSe_(2) on Bernal tetralayer graphene to investigate the influence of SOI on the anomalous Hall effect(AHE).In this structurally asymmetric device,by comparing the magnitude of AHE at positive and negative displacement fields,we find that AHE is strongly enhanced by bringing electrons in proximity to the WSe_(2) layer.Meanwhile,the enhanced AHE signal persists up to 80 K,providing important routes for topological device applications at high temperatures.展开更多
Here,we report the spin-orbit state-resolved differential cross sections(DCSs)for the prototype barrierless reaction S(^(1)D)+HD.Both product channels,namely H+SD(^(2)Π_(3/2,1/2))and D+SH(^(2)Π_(3/2,1/2)),were measu...Here,we report the spin-orbit state-resolved differential cross sections(DCSs)for the prototype barrierless reaction S(^(1)D)+HD.Both product channels,namely H+SD(^(2)Π_(3/2,1/2))and D+SH(^(2)Π_(3/2,1/2)),were measured by high-resolution crossed molecular beam experiments.The DCSs of the two product channels show an overall forward-backward symmetry,in accordance with statistical model predictions.However,the DCSs for different spin-orbit manifolds show different preferences in forward or backward scattering directions at the same collision energies.This study reveals that,even though the title reaction proceeds via the long-lived complex mechanism,the spin-orbit coupling effects in the product channels play an important role in the reaction process.展开更多
In-memory computing(IMC)based on spin-logic devices is regarded as an advantageous way to optimize the Von Neumann bottleneck.However,performing complete Boolean logic with spintronic devices typi-cally requires an in...In-memory computing(IMC)based on spin-logic devices is regarded as an advantageous way to optimize the Von Neumann bottleneck.However,performing complete Boolean logic with spintronic devices typi-cally requires an initialization operation,which can reduce processing speed.In this work,we conceptu-alize and experimentally demonstrate a programmable and initialization-free spin-logic gate,leveraging spin-orbit torque(SOT)to effectuate magnetization switching,assisted by in-plane Oersted field gener-ated by an integrated bias-field Au line.This spin-logic gate,fabricated as a Hall bar,allows complete Boolean logic operations without initialization.A current flowing through the bias-field line,which is electrically isolated from the device by a dielectric,generates an in-plane magnetic field that can invert the SOT-induced switching chirality,enabling on-the-fly complete Boolean logic operations.Additionally,the device demonstrated good reliability,repeatability,and reproducibility during logic operations.Our work demonstrates programmable and scalable spin-logic functions in a single device,offering a new approach for spin-logic operations in an IMC architecture.展开更多
Interlayer exchange coupling(IEC)plays a critical role in spin-orbit torque(SOT)switching in synthetic magnets.This work establishes a fundamental correlation between IEC and SOT dynamics within Co/Pt-based synthetic ...Interlayer exchange coupling(IEC)plays a critical role in spin-orbit torque(SOT)switching in synthetic magnets.This work establishes a fundamental correlation between IEC and SOT dynamics within Co/Pt-based synthetic antiferromagnets and synthetic ferromagnets.The antiferromagnetic and ferromagnetic coupling states are precisely engineered through Ruderman-Kittel-Kasuya-Yosida(RKKY)interactions by modulating the Ir spacer thickness.Experimental results reveal that the critical switching current density exhibits a strong positive correlation with the IEC strength,regardless of the coupling type.A comprehensive theoretical framework based on the Landau-Lifshitz-Gilbert equation elucidates how IEC contributes to the effective energy barrier that must be overcome during SOT-induced magnetization switching.Significantly,the antiferromagnetically coupled samples demonstrate enhanced SOT efficiency,with the spin Hall angle being directly proportional to the antiferromagnetic exchange coupling field.These insights establish a coherent physical paradigm for understanding IEC-dependent SOT dynamics and provide strategic design principles for the development of energy-efficient next-generation spintronic devices.展开更多
We consider matter-wave solitons in spin-orbit coupled Bose-Einstein condensates embedded in an optical lattice and study the dynamics of the soliton within the framework of Gross-Pitaevskii equations.We express spin ...We consider matter-wave solitons in spin-orbit coupled Bose-Einstein condensates embedded in an optical lattice and study the dynamics of the soliton within the framework of Gross-Pitaevskii equations.We express spin components of the soliton pair in terms of nonlinear Bloch equations and investigate the effective spin dynamics.It is seen that the effective magnetic field that appears in the Bloch equation is affected by optical lattices,and thus the optical lattice influences the precessional frequency of the spin components.We make use of numerical approaches to investigate the dynamical behavior of density profiles and center-of-mass of the soliton pair in the presence of the optical lattice.It is shown that the spin density is periodically varying due to flipping of spinors between the two states.The amplitude of spin-flipping oscillation increases with lattice strength.We find that the system can also exhibit interesting nonlinear behavior for chosen values of parameters.We present a fixed point analysis to study the effects of optical lattices on the nonlinear dynamics of the spin components.It is seen that the optical lattice can act as a control parameter to change the dynamical behavior of the spin components from periodic to chaotic.展开更多
In this paper, we obtain considerable spin-orbit （SO） parameters in AlxGa1-xN/GaN quantum wells （QWs） with sheet carrier concentration N8 = 120 × 10^11/cm^2. With increasing AI content （x） of the barrier, t...In this paper, we obtain considerable spin-orbit （SO） parameters in AlxGa1-xN/GaN quantum wells （QWs） with sheet carrier concentration N8 = 120 × 10^11/cm^2. With increasing AI content （x） of the barrier, the SO parameters increase as a whole, and the two major contributions are found to be the decrease of the expansion region of the envelope functions and the increase of the polarized electric field in the well. Compared with the Rashba parameters for the first two subbands, the intersubband SO parameter is a bit smaller and varies more slowly with x. The results indicate the SO parameters, especially the Rashba parameters can be engineered by the AI composition of the barrier, which may be helpful to the spin manipulation of III-nitride low-dimensional heterostructures.展开更多
Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spati...Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spatially asymmetrical beam,similar to the electric field breaking the symmetry in spin Hall effect for electrons.The angular momentum(AM)conservation law in the ensuing asymmetric system dictates redistribution of spin and orbital angular momentum,and is manifested in spin-orbit,orbit-orbit,and orbit-spin conversions and reorganization,i.e.spin-orbit and orbit-orbit interaction.This AM restructuring in turn requires shifts of the barycenter of the electric field of light.In the present study we show,both analytically and by numerical simulation,how different electric field components are displaced upon tight focusing of an asymmetric light beam having OAM and spin.The relation between field components shifts and the AM components shifts/redistribution is presented too.Moreover,we experimentally demonstrate,for the first time,to the best of our knowledge,the spin-orbit Hall effect of light upon tight focusing in free space.This is achieved using azopolymers as a media detecting longitudinal or z component of the electrical field of light.These findings elucidate the Hall effect of light and may broaden the spectrum of its applications.展开更多
By investigating a harmonically confined and periodically driven particle system with spin-orbit coupling(SOC)and a specific controlled parameter,we demonstrate an exactly solvable two-level model with a complete set ...By investigating a harmonically confined and periodically driven particle system with spin-orbit coupling(SOC)and a specific controlled parameter,we demonstrate an exactly solvable two-level model with a complete set of spin-motion entangled Schrödinger kitten(or cat)states.In the undriven case,application of a modulation resonance results in the exact stationary states.We show a decoherence-averse effect of SOC and implement a transparent coherent control by exchanging positions of the probability-density wavepackets to create transitions between the different degenerate ground states.The expected energy consisting of quantum and continuous parts is derived,and the energy deviations caused by the exchange operations are much less than the quantum gap.The results could be directly extended to a weakly coupled single-particle chain for transparently encoding spin-orbit qubits via the robust spin-motion entangled degenerate ground states.展开更多
The current-induced spin-orbit torque(SOT)plays a dominant role to manipulate the magnetization in a heavy metal/ferromagnetic metal bilayer.We separate the contributions of interfacial and bulk spin-orbit coupling(SO...The current-induced spin-orbit torque(SOT)plays a dominant role to manipulate the magnetization in a heavy metal/ferromagnetic metal bilayer.We separate the contributions of interfacial and bulk spin-orbit coupling(SOC)to the effective field of field-like SOT in a typical NiFe/Pt bilayer by planar Hall effect(PHE).The effective field from interfacial SOC is directly measured at the transverse PHE configuration.Then,at the longitudinal configuration,the effective field from bulk SOC is determined,which is much smaller than that from interfacial SOC.The giant interface SOT in NiFe/Pt bilayers suggests that further analysis of interfacial effects on the current-induced manipulation of magnetization is necessary.展开更多
Spin-orbit optical phenomena pertain to the wider class of electromagnetic effects originating from the interaction of the photon spin with the spatial structure and propagation characteristics of an optical wave,medi...Spin-orbit optical phenomena pertain to the wider class of electromagnetic effects originating from the interaction of the photon spin with the spatial structure and propagation characteristics of an optical wave,mediated by suitable optical media.There are many emerging photonic applications of spin-orbit interactions(SOI)of light,such as control of the optical wave propagation via the spin,enhanced optical manipulation,and generation of structured optical fields.Unfortunately,current applications are based on symmetric SOI,that is,the behaviours of polarized photons with two opposite spins are opposite,leading to the limit of spin-based multiplexers.The symmetry of SOI can be broken in our proposed metasurfaces,consisting of spatially varying birefringence,which can arbitrarily and independently build SOI for two opposite spins without reduction of optical energy usage.We obtain three kinds of dual-functional metasurfaces at visible and infrared wavelengths with high efficiency.Our concept of generation of asymmetric SOI for two spins,using anisotropic metasurfaces,will open new degrees of freedoms for building new types of spin-controlled multifunctional shared-aperture devices for the generation of complex structured optical fields.展开更多
The binding energy spectrum and electron momentum distributions for the outer valence orbitals of n-propyl iodide molecule have been measured using the electron momentum spectrometer employing non-coplanar asymmetric ...The binding energy spectrum and electron momentum distributions for the outer valence orbitals of n-propyl iodide molecule have been measured using the electron momentum spectrometer employing non-coplanar asymmetric geometry at impact energy of 2.5 keV plus binding energy. The ionization bands have been assigned in detail via the high accuracy SACCI general-R method calculation and the experimental momentum profiles are compared with the theoretical ones calculated by Hartree-Fock and B3LYP/aug-cc-pVTZ（C,H）6-311G？？（I）. The spin-orbit coupling effect and intramolecular orbital interaction have been analyzed for the outermost two bands, which are assigned to the iodine 5p lone pairs, using NBO method and non-relativistic as well as relativistic calculations. It is found that both of the interactions will lead to the observed differences in electron momentum distributions. The experimental results agree with the relativistic theoretical momentum profiles, indicating that the spin-orbit coupling effect dominates in n-propyl iodide molecule.展开更多
We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. O...We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron area/density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron＇s, the spin-splitting states of the polaron are more stable than electron＇s.展开更多
Spinel LiMn_(2)O_(4)is recognized as one of the most competitive cathode candidates for lithium-ion batteries ascribed to environmentally benign and rich sources.However,the wholesale application of LiMn_(2)O_(4)is pr...Spinel LiMn_(2)O_(4)is recognized as one of the most competitive cathode candidates for lithium-ion batteries ascribed to environmentally benign and rich sources.However,the wholesale application of LiMn_(2)O_(4)is predominately plagued by its severe capacity degradation,mainly associated with the innate Jahn-Teller effect.Herein,single-crystalline LiMn_(2)O_(4)with Eu^(3+) doping is rationally designed to mitigate the detrimental Jahn-Teller distortion by tuning the chemical environment of MnO_(6) octahedra and accommodating localized electron,based on the unique aspheric flexible 4f electron orbit of rare-earth metal ions.Notably,the stretching of MnO_(6) octahedron stemmed from the Jahn-Teller effect in Eu-doped LiMn_(2)O_(4)is effectively suppressed,confirmed by theoretical calculation.Meanwhile,the structural stability of the material has been significantly enhanced due to the robust Mn–O band coherency and weakened phase transition,proved by synchrotron radiation absorption spectrum and operando X-ray diffraction.The corresponding active cathode manifests superior long-cycle stability after 300 loops at 2C and displays only a 0.011%capacity drop per cycle even at 5C.Given this,this modification tactic sheds new light on achieving superior long-cycle performances by suppressing distortion in various cathode materials.展开更多
Spin-orbit scattering effects in a layered quasi-2D disordered electron system have been investigated by the diagrammatic techniques in perturbation theory. The expression of Cooperon (propagator in particle-particle ...Spin-orbit scattering effects in a layered quasi-2D disordered electron system have been investigated by the diagrammatic techniques in perturbation theory. The expression of Cooperon (propagator in particle-particle channel) is obtained as the function of interlayer coupling. The analytical result for the quantum correction to Hall conductivity has been obtained as functions of elastic, inelastic and spin-orbit scattering times. It is shown that the strong and weak couplings correspond, respectively, to the 3D and 2D situations. The Hall coefficient is shown to vanish. The relevant dimensional crossover behavior from 3D to 2D with decreasing the interlayer coupling has been discussed, and the condition for the crossover has been obtained. The present theory is expected to apply for the electronic transport in tunneling superlattices.展开更多
We have investigated theoretically the field-driven electron-transport through a double-quantum-well semiconductor-heterostructure with spin-orbit coupling. The numerical results demonstrate that the transmission spec...We have investigated theoretically the field-driven electron-transport through a double-quantum-well semiconductor-heterostructure with spin-orbit coupling. The numerical results demonstrate that the transmission spectra are divided into two sets due to the bound-state level-splitting and each set contains two asymmetric resonance peaks which may be selectively suppressed by changing the difference in phase between two driving fields. When the phase difference changes from 0 to π, the dip of asymmetric resonance shifts from one side of resonance peak to the other side and the asymmetric Fano resonance degenerates into the symmetric Breit-Wigner resonance at a critical value of phase difference. Within a given range of incident electron energy, the spin polarization of transmission current is completely governed by the phase difference which may be used to realize the tunable spin filtering.展开更多
We study theoretically the transmission coefficients and the spin-tunneling time in ferromagnetic/semiconductor/ferromagnetic three-terminal heterojunction in the presence of Rashba spin-orbit interaction, in which on...We study theoretically the transmission coefficients and the spin-tunneling time in ferromagnetic/semiconductor/ferromagnetic three-terminal heterojunction in the presence of Rashba spin-orbit interaction, in which onedimensional quantum waveguide theory is developed and applied. Based on the group velocity concept and the particle current conservation principle, we calculate the spin-tunneling time as the function of the intensity of Rashba spinrblt coupling and the length of the semiconductor. We find that as the length of the semiconductor increases, the spintunneling time does not increase linearly but shows behavior of slight oscillation, i;brthermore, with the increasing of the soin-orbit coupling, the spin-tunneling time increases.展开更多
基金supported by the Beijing Natural Science Foundation(Grant No.Z230006)the National Key Research and Development Program of China(Grant No.2022YFA1204000)the National Natural Science Foundation of China(Grant Nos.12274405 and 12393831)。
文摘We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate that the efficiency of the spin-orbit torque increases nearly linearly with the repetition number n,which is in excellent agreement with the spin Hall effect of the Pt_(0.75)Ti_(0.25)being essentially the only source of the observed spin-orbit torque.The perpendicular magnetic anisotropy field is also substantially enhanced by more than a factor of 2 as n increases from 1 to6.The[Pt_(0.75)Ti_(0.25)/Co-Ni multilayers/Ta]_n superlattice additionally exhibits deterministic,low-current-density magnetization switching despite the very large total layer thicknesses.The unique combination of strong spin-orbit torque,robust perpendicular magnetic anisotropy,low-current-density switching,and excellent high thermal stability makes the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice a highly compelling material candidate for ultrafast,energy-efficient,and long-data-retention spintronic technologies.
基金supported by the National Natural Science Foundation of China(NSFC,No.22090041)the Guangdong Basic and Applied Basic Research Foundation(No.2022B1515120014)。
文摘Spin-orbit coupling(SOC)plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved.Here,the prototypical perovskite iridate oxide SrIrO_(3)is investigated to gain more insights into the SOC effect in the modification of electronic structure and corresponding magnetic and electrical properties.The high pressure metastable orthorhombic SrIrO_(3)is successfully stabilized by physical and chemical pressures,in which the chemical pressure is induced by Ru doping in Ir site and Mg substitution of Sr position.Detailed structural,magnetic,electrical characterizations and density functional theory(DFT)calculations reveal that the substitution of Ru for Ir renders an enhanced metallic characteristic,while the introduction of Mg into Sr site results in an insulating state with 10.1%negative magnetoresistance at 10 K under 7 T.Theoretical calculations indicate that Ru doping can weaken the SOC effect,leading to the decrease of orbital energy difference between J_(1/2)and J_(3/2),which is favorable for electron transport.On the contrary,Mg doping can enhance the SOC effect,inducing a metal-insulator-transition(MIT).The electronic phase transition is further revealed by DFT calculations,confirming that the strong SOC and electron-electron interactions can lead to the emergence of insulating state.These findings underline the intricate correlations between lattice degrees of freedom and SOC in determining the ground state,which effectively stimulate the physical pressure between like structures by chemical compression.
基金financial support from the National Key R&D Program of China(Nos.2022YFB3506000 and 2022YFA1602700)financial support from Fundamental Research Funds for the Central Universities+6 种基金financial support from the National Natural Science Foundation of China(Nos.52425106,52121001,and 52271235)financial support from the Beijing Natural Science Foundation(No.JQ23005)financial support from the National Natural Science Foundation of China(No.52401300)funding from the China National Postdoctoral Program for Innovative Talents(No.BX20230451)from the China Postdoctoral Science Foundation(No.2024M754058)financial support from the National Natural Science Foundation of China(No.62401276)financial support from the National Natural Science Foundation of China(No.524B2003).
文摘Ferrimagnets are important for next-generation high-density ultrafast spintronic device applications.Magnetization compensation temperature(TM)is a fundamentally critical magnetic parameter for ferrimagnets besides their Curie temperature.Around TM,the spin-orbit switching efficiencies are extraordinarily high.Therefore,the accurate manipulation of TM from the material fabrication process is essential for the electrical steering of ferrimagnetic spins.In this work,CoTb thin films,with the 3 d and 4 f magnetic sublattices antiferromagnetically coupled to each other,are deposited at different temperatures.The magnetotransport and magnetic properties of these films are systematically investigated.It was found that the TM of this rare-earth ferrimagnet largely depends on the growth temperature and it can be tuned by over 100 K.Accordingly,the spins of an optimized ferrimagnetic CoTb thin film with its TM close to room temperature can be efficiently switched by the current-pulse-induced spin-orbit torque.Moreover,an artificial neural network utilizing the spin-orbit torque device was constructed,demonstrating an image recognition accuracy of approximately 92.5%,which is comparable to that of conventional software solutions.Thus,this work demonstrates the large tunability of TM of a rare earth ferrimagnet by chemical ordering and the great potential of such a ferrimagnet for electrically operated spintronic devices.
基金supported by the National Natural Science Foundation of China(Grant No.11974331)。
文摘We study the trimer state in a three-body system,where two of the atoms are subject to Rashba-type spin-orbit coupling and spin-dependent loss while interacting spin-selectively with the third atom.The short-time conditional dynamics of the three-body system is effectively governed by a non-Hermitian Hamiltonian with an imaginary Zeeman field.Remarkably,the interplay of non-Hermitian single particle dispersion and the spin-selective interaction results in a Borromean state and an enlarged trimer phase.The stability of trimer state can be reflected by the imaginary part of trimer energy and the momentum distribution of trimer wave function.We also show the phase diagram of the three-body system under both real and imaginary Zeeman fields.Our results illustrate the interesting consequence of non-Hermitian spectral symmetry on the few-body level,which may be readily observable in current cold-atom experiments.
基金Project supported by the National Key R&D Program of China(Grant Nos.2021YFA1400100 and 2024YFA1409700)the National Natural Science Foudation of China(Grant Nos.12374168 and T2325026)。
文摘Spin-orbit interaction(SOI)can be introduced by the proximity effect to modulate the electronic properties of graphene-based heterostructures.In this work,we stack trilayer WSe_(2) on Bernal tetralayer graphene to investigate the influence of SOI on the anomalous Hall effect(AHE).In this structurally asymmetric device,by comparing the magnitude of AHE at positive and negative displacement fields,we find that AHE is strongly enhanced by bringing electrons in proximity to the WSe_(2) layer.Meanwhile,the enhanced AHE signal persists up to 80 K,providing important routes for topological device applications at high temperatures.
基金supported by the National Natural Science Foundation of China(Nos.92476207,22288201)the Chinese Academy of Sciences(No.XBD0970202)+2 种基金the Innovation Program for Quantum Science and Technology(No.2021ZD0303300)the Shenzhen Science and Technology Innovation Committee(No.20220814164755002)the Guangdong Innovative&Entrepreneurial Research Team Program(Nos.2019ZT08L455,2019JC01X091).
文摘Here,we report the spin-orbit state-resolved differential cross sections(DCSs)for the prototype barrierless reaction S(^(1)D)+HD.Both product channels,namely H+SD(^(2)Π_(3/2,1/2))and D+SH(^(2)Π_(3/2,1/2)),were measured by high-resolution crossed molecular beam experiments.The DCSs of the two product channels show an overall forward-backward symmetry,in accordance with statistical model predictions.However,the DCSs for different spin-orbit manifolds show different preferences in forward or backward scattering directions at the same collision energies.This study reveals that,even though the title reaction proceeds via the long-lived complex mechanism,the spin-orbit coupling effects in the product channels play an important role in the reaction process.
基金supported by the National Science and Technology Major Project(2020AAA0109005)the National Natural Science Foundation of China(62374055,12327806,62304083,62074063,61821003,61904060,61904051,61674062)+4 种基金the Interdisciplinary Program of Wuhan National High Magnetic Field Center(WHMFC202119)the Shenzhen Science and Technology Program Award(JCYJ20220818103410022)the Shenzhen Virtual University Park(2021Szvup091)the Natural Science Foundation of Wuhan(2024040701010049)Shuai Zhang acknowledges support from the China Postdoctoral Science Foundation(2022M721237).
文摘In-memory computing(IMC)based on spin-logic devices is regarded as an advantageous way to optimize the Von Neumann bottleneck.However,performing complete Boolean logic with spintronic devices typi-cally requires an initialization operation,which can reduce processing speed.In this work,we conceptu-alize and experimentally demonstrate a programmable and initialization-free spin-logic gate,leveraging spin-orbit torque(SOT)to effectuate magnetization switching,assisted by in-plane Oersted field gener-ated by an integrated bias-field Au line.This spin-logic gate,fabricated as a Hall bar,allows complete Boolean logic operations without initialization.A current flowing through the bias-field line,which is electrically isolated from the device by a dielectric,generates an in-plane magnetic field that can invert the SOT-induced switching chirality,enabling on-the-fly complete Boolean logic operations.Additionally,the device demonstrated good reliability,repeatability,and reproducibility during logic operations.Our work demonstrates programmable and scalable spin-logic functions in a single device,offering a new approach for spin-logic operations in an IMC architecture.
基金Project supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang Province(Grant No.2022C01053)the Key Research and Development Program of Zhejiang Province(Grant No.2021C01039)+1 种基金the National Natural Science Foundation of China(Grant No.62293493)the Natural Science Foundation of Zhejiang Province,China(Grant No.LQ21A050001)。
文摘Interlayer exchange coupling(IEC)plays a critical role in spin-orbit torque(SOT)switching in synthetic magnets.This work establishes a fundamental correlation between IEC and SOT dynamics within Co/Pt-based synthetic antiferromagnets and synthetic ferromagnets.The antiferromagnetic and ferromagnetic coupling states are precisely engineered through Ruderman-Kittel-Kasuya-Yosida(RKKY)interactions by modulating the Ir spacer thickness.Experimental results reveal that the critical switching current density exhibits a strong positive correlation with the IEC strength,regardless of the coupling type.A comprehensive theoretical framework based on the Landau-Lifshitz-Gilbert equation elucidates how IEC contributes to the effective energy barrier that must be overcome during SOT-induced magnetization switching.Significantly,the antiferromagnetically coupled samples demonstrate enhanced SOT efficiency,with the spin Hall angle being directly proportional to the antiferromagnetic exchange coupling field.These insights establish a coherent physical paradigm for understanding IEC-dependent SOT dynamics and provide strategic design principles for the development of energy-efficient next-generation spintronic devices.
文摘We consider matter-wave solitons in spin-orbit coupled Bose-Einstein condensates embedded in an optical lattice and study the dynamics of the soliton within the framework of Gross-Pitaevskii equations.We express spin components of the soliton pair in terms of nonlinear Bloch equations and investigate the effective spin dynamics.It is seen that the effective magnetic field that appears in the Bloch equation is affected by optical lattices,and thus the optical lattice influences the precessional frequency of the spin components.We make use of numerical approaches to investigate the dynamical behavior of density profiles and center-of-mass of the soliton pair in the presence of the optical lattice.It is shown that the spin density is periodically varying due to flipping of spinors between the two states.The amplitude of spin-flipping oscillation increases with lattice strength.We find that the system can also exhibit interesting nonlinear behavior for chosen values of parameters.We present a fixed point analysis to study the effects of optical lattices on the nonlinear dynamics of the spin components.It is seen that the optical lattice can act as a control parameter to change the dynamical behavior of the spin components from periodic to chaotic.
文摘In this paper, we obtain considerable spin-orbit （SO） parameters in AlxGa1-xN/GaN quantum wells （QWs） with sheet carrier concentration N8 = 120 × 10^11/cm^2. With increasing AI content （x） of the barrier, the SO parameters increase as a whole, and the two major contributions are found to be the decrease of the expansion region of the envelope functions and the increase of the polarized electric field in the well. Compared with the Rashba parameters for the first two subbands, the intersubband SO parameter is a bit smaller and varies more slowly with x. The results indicate the SO parameters, especially the Rashba parameters can be engineered by the AI composition of the barrier, which may be helpful to the spin manipulation of III-nitride low-dimensional heterostructures.
基金supported by the Russian Science Foundation grant No.22-79-10007.
文摘Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spatially asymmetrical beam,similar to the electric field breaking the symmetry in spin Hall effect for electrons.The angular momentum(AM)conservation law in the ensuing asymmetric system dictates redistribution of spin and orbital angular momentum,and is manifested in spin-orbit,orbit-orbit,and orbit-spin conversions and reorganization,i.e.spin-orbit and orbit-orbit interaction.This AM restructuring in turn requires shifts of the barycenter of the electric field of light.In the present study we show,both analytically and by numerical simulation,how different electric field components are displaced upon tight focusing of an asymmetric light beam having OAM and spin.The relation between field components shifts and the AM components shifts/redistribution is presented too.Moreover,we experimentally demonstrate,for the first time,to the best of our knowledge,the spin-orbit Hall effect of light upon tight focusing in free space.This is achieved using azopolymers as a media detecting longitudinal or z component of the electrical field of light.These findings elucidate the Hall effect of light and may broaden the spectrum of its applications.
基金the National Natural Science Foundation of China(Grant Nos.11204077 and 11475060)the Natural Science Foundation of Hunan Province,China(Grant No.2019JJ10002)+1 种基金the Hunan Provincial Hundred People Plan,China(2019)the Science and Technology Plan Project of Hunan Province,China.
文摘By investigating a harmonically confined and periodically driven particle system with spin-orbit coupling(SOC)and a specific controlled parameter,we demonstrate an exactly solvable two-level model with a complete set of spin-motion entangled Schrödinger kitten(or cat)states.In the undriven case,application of a modulation resonance results in the exact stationary states.We show a decoherence-averse effect of SOC and implement a transparent coherent control by exchanging positions of the probability-density wavepackets to create transitions between the different degenerate ground states.The expected energy consisting of quantum and continuous parts is derived,and the energy deviations caused by the exchange operations are much less than the quantum gap.The results could be directly extended to a weakly coupled single-particle chain for transparently encoding spin-orbit qubits via the robust spin-motion entangled degenerate ground states.
基金the National Natural Science Foundation of China(Grant No.11574375).
文摘The current-induced spin-orbit torque(SOT)plays a dominant role to manipulate the magnetization in a heavy metal/ferromagnetic metal bilayer.We separate the contributions of interfacial and bulk spin-orbit coupling(SOC)to the effective field of field-like SOT in a typical NiFe/Pt bilayer by planar Hall effect(PHE).The effective field from interfacial SOC is directly measured at the transverse PHE configuration.Then,at the longitudinal configuration,the effective field from bulk SOC is determined,which is much smaller than that from interfacial SOC.The giant interface SOT in NiFe/Pt bilayers suggests that further analysis of interfacial effects on the current-induced manipulation of magnetization is necessary.
基金supported by 973 Program of China (2013CBA01700)National Natural Science Funds (61622508, 61575032)
文摘Spin-orbit optical phenomena pertain to the wider class of electromagnetic effects originating from the interaction of the photon spin with the spatial structure and propagation characteristics of an optical wave,mediated by suitable optical media.There are many emerging photonic applications of spin-orbit interactions(SOI)of light,such as control of the optical wave propagation via the spin,enhanced optical manipulation,and generation of structured optical fields.Unfortunately,current applications are based on symmetric SOI,that is,the behaviours of polarized photons with two opposite spins are opposite,leading to the limit of spin-based multiplexers.The symmetry of SOI can be broken in our proposed metasurfaces,consisting of spatially varying birefringence,which can arbitrarily and independently build SOI for two opposite spins without reduction of optical energy usage.We obtain three kinds of dual-functional metasurfaces at visible and infrared wavelengths with high efficiency.Our concept of generation of asymmetric SOI for two spins,using anisotropic metasurfaces,will open new degrees of freedoms for building new types of spin-controlled multifunctional shared-aperture devices for the generation of complex structured optical fields.
文摘The binding energy spectrum and electron momentum distributions for the outer valence orbitals of n-propyl iodide molecule have been measured using the electron momentum spectrometer employing non-coplanar asymmetric geometry at impact energy of 2.5 keV plus binding energy. The ionization bands have been assigned in detail via the high accuracy SACCI general-R method calculation and the experimental momentum profiles are compared with the theoretical ones calculated by Hartree-Fock and B3LYP/aug-cc-pVTZ（C,H）6-311G？？（I）. The spin-orbit coupling effect and intramolecular orbital interaction have been analyzed for the outermost two bands, which are assigned to the iodine 5p lone pairs, using NBO method and non-relativistic as well as relativistic calculations. It is found that both of the interactions will lead to the observed differences in electron momentum distributions. The experimental results agree with the relativistic theoretical momentum profiles, indicating that the spin-orbit coupling effect dominates in n-propyl iodide molecule.
基金The project supported by National Natural Science Foundation of China under Grant No. 10347004.
文摘We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron area/density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron＇s, the spin-splitting states of the polaron are more stable than electron＇s.
基金financially supported by the National Natural Science Foundation of China(U21A20284)the National Key Research and Development Program of China(2019YFC1907805)the Fundamental Research Funds for the Central Universities of Central South University(2021zzts0072)。
文摘Spinel LiMn_(2)O_(4)is recognized as one of the most competitive cathode candidates for lithium-ion batteries ascribed to environmentally benign and rich sources.However,the wholesale application of LiMn_(2)O_(4)is predominately plagued by its severe capacity degradation,mainly associated with the innate Jahn-Teller effect.Herein,single-crystalline LiMn_(2)O_(4)with Eu^(3+) doping is rationally designed to mitigate the detrimental Jahn-Teller distortion by tuning the chemical environment of MnO_(6) octahedra and accommodating localized electron,based on the unique aspheric flexible 4f electron orbit of rare-earth metal ions.Notably,the stretching of MnO_(6) octahedron stemmed from the Jahn-Teller effect in Eu-doped LiMn_(2)O_(4)is effectively suppressed,confirmed by theoretical calculation.Meanwhile,the structural stability of the material has been significantly enhanced due to the robust Mn–O band coherency and weakened phase transition,proved by synchrotron radiation absorption spectrum and operando X-ray diffraction.The corresponding active cathode manifests superior long-cycle stability after 300 loops at 2C and displays only a 0.011%capacity drop per cycle even at 5C.Given this,this modification tactic sheds new light on achieving superior long-cycle performances by suppressing distortion in various cathode materials.
文摘Spin-orbit scattering effects in a layered quasi-2D disordered electron system have been investigated by the diagrammatic techniques in perturbation theory. The expression of Cooperon (propagator in particle-particle channel) is obtained as the function of interlayer coupling. The analytical result for the quantum correction to Hall conductivity has been obtained as functions of elastic, inelastic and spin-orbit scattering times. It is shown that the strong and weak couplings correspond, respectively, to the 3D and 2D situations. The Hall coefficient is shown to vanish. The relevant dimensional crossover behavior from 3D to 2D with decreasing the interlayer coupling has been discussed, and the condition for the crossover has been obtained. The present theory is expected to apply for the electronic transport in tunneling superlattices.
基金supported by the National Natural Science Foundation of China (Grant Nos 10475053,10775091 and 10774094)the Shanxi Natural Science Foundation,China (Grant No 20051002)
文摘We have investigated theoretically the field-driven electron-transport through a double-quantum-well semiconductor-heterostructure with spin-orbit coupling. The numerical results demonstrate that the transmission spectra are divided into two sets due to the bound-state level-splitting and each set contains two asymmetric resonance peaks which may be selectively suppressed by changing the difference in phase between two driving fields. When the phase difference changes from 0 to π, the dip of asymmetric resonance shifts from one side of resonance peak to the other side and the asymmetric Fano resonance degenerates into the symmetric Breit-Wigner resonance at a critical value of phase difference. Within a given range of incident electron energy, the spin polarization of transmission current is completely governed by the phase difference which may be used to realize the tunable spin filtering.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10574036 and 10574U37, and Natural Science Foundation of Hebei Province of China under Grant Nos. A2004000141 and 2005000143
文摘We study theoretically the transmission coefficients and the spin-tunneling time in ferromagnetic/semiconductor/ferromagnetic three-terminal heterojunction in the presence of Rashba spin-orbit interaction, in which onedimensional quantum waveguide theory is developed and applied. Based on the group velocity concept and the particle current conservation principle, we calculate the spin-tunneling time as the function of the intensity of Rashba spinrblt coupling and the length of the semiconductor. We find that as the length of the semiconductor increases, the spintunneling time does not increase linearly but shows behavior of slight oscillation, i;brthermore, with the increasing of the soin-orbit coupling, the spin-tunneling time increases.
