The interplay of the Rashba effect and the spin Hall effect originating from current induced spin–orbit coupling was investigated in the as-deposited and annealed Pt/Co/MgO stacks with perpendicular magnetic anisotro...The interplay of the Rashba effect and the spin Hall effect originating from current induced spin–orbit coupling was investigated in the as-deposited and annealed Pt/Co/MgO stacks with perpendicular magnetic anisotropy. The above two effects were analyzed based on Hall measurements under external magnetic fields longitudinal and vertical to dc current,respectively. The coercive field as a function of dc current in vertical mode with only the Rashba effect involved decreases due to thermal annealing. Meanwhile, spin orbit torques calculated from Hall resistance with only the spin Hall effect involved in the longitudinal mode decrease in the annealed sample. The experimental results prove that the bottom Pt/Co interface rather than the Co/MgO top one plays a more critical role in both Rashba effect and spin Hall effect.展开更多
The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its...The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.展开更多
The properties of the weakly-coupling bound polaron, considering an influence of Rashba effect, which is brought about by the spin-orbit （SO） interaction, in an semiconductor triangular quantum well （TQW）, have be...The properties of the weakly-coupling bound polaron, considering an influence of Rashba effect, which is brought about by the spin-orbit （SO） interaction, in an semiconductor triangular quantum well （TQW）, have been studied by using the linear combination operator and the unitary transformation methods. We obtain an expression for the ground state energy of the weak-coupling and bound polaron in a TQW as a function of the coupling constant, Coulomb bound potential, and the electron areal density. Our numerical resuks show that the ground state energy of the polaron is composed of four parts, one part is caused by the electrons＇ own energy, the second part is caused by the Rashba effect, the third part occurs because of the Coulomb bound potential, and the last term is induced by the interaction between the electrons and LO phonons. The interactions between the orbit and the spin with different directions have different effects on the ground state energy of the polaron.展开更多
Rashba effect in presence of a time-dependent interaction has been considered.Then time-evolution of such a system has been studied by using Lewis–Riesenfeld dynamical invariant and unitary transformation method.So a...Rashba effect in presence of a time-dependent interaction has been considered.Then time-evolution of such a system has been studied by using Lewis–Riesenfeld dynamical invariant and unitary transformation method.So appropriate dynamical invariant and unitary transformation according the considered system have been constructed as well as some special cases have come into this article which are common in physics.展开更多
With the support by the National Natural Science Foundation of China,a study by the research group led by Prof.Luo Junwei(骆军委)from the Institute of Semiconductors,Chinese Academy of Sciences discovered a rapid tran...With the support by the National Natural Science Foundation of China,a study by the research group led by Prof.Luo Junwei(骆军委)from the Institute of Semiconductors,Chinese Academy of Sciences discovered a rapid transition of the hole Rashba effect from strong field dependence to saturation展开更多
PtTe2 and PtSe2 with trigonal structure have attracted extensive research interests since the discovery of type-II Dirac fermions in the bulk crystals. The evolution of the electronic structure from bulk 3D topologica...PtTe2 and PtSe2 with trigonal structure have attracted extensive research interests since the discovery of type-II Dirac fermions in the bulk crystals. The evolution of the electronic structure from bulk 3D topological semimetal to 2D atomic thin films is an important scientific question. While a transition from 3D type-II Dirac semimetal in the bulk to 2D semiconductor in monolayer(ML) film has been reported for PtSe2, so far the evolution of electronic structure of atomically thin PtTe2 films still remains unexplored.Here we report a systematic angle-resolved photoemission spectroscopy(ARPES) study of the electronic structure of high quality PtTe2 films grown by molecular beam epitaxy with thickness from 2 ML to 6 ML.ARPES measurements show that PtTe2 films still remain metallic even down to 2 ML thickness, which is in sharp contrast to the semiconducting property of few layer PtSe2 films. Moreover, a transition from 2D metal to 3D type-II Dirac semimetal occurs at film thickness of 4–6 ML. In addition, Spin-ARPES measurements reveal helical spin textures induced by local Rashba effect in the bulk PtTe2 crystal, suggesting that similar hidden spin is also expected in few monolayer PtTe2 films. Our work reveals the transition from2D metal to 3D topological semimetal and provides new opportunities for investigating metallic 2D films with local Rashba effect.展开更多
The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Ah...The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Aharonov-Bohm interferometer are investigated by means of the Green function technique. The periodic Anderson model is used to describe the quantum dot system, the Rashba spin-orbit interaction and the Zeeman splitting under a magnetic field are considered. The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects. We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2015CB921401)the National Natural Science Foundation of China(Grant Nos.51331002,51371027,51431009,51471183,and 11274371)+1 种基金the National Instrumentation Program of China(Grant No.2012YQ120048)the Instrument Development Program of Chinese Academy of Sciences(Grant No.YZ201345)
文摘The interplay of the Rashba effect and the spin Hall effect originating from current induced spin–orbit coupling was investigated in the as-deposited and annealed Pt/Co/MgO stacks with perpendicular magnetic anisotropy. The above two effects were analyzed based on Hall measurements under external magnetic fields longitudinal and vertical to dc current,respectively. The coercive field as a function of dc current in vertical mode with only the Rashba effect involved decreases due to thermal annealing. Meanwhile, spin orbit torques calculated from Hall resistance with only the spin Hall effect involved in the longitudinal mode decrease in the annealed sample. The experimental results prove that the bottom Pt/Co interface rather than the Co/MgO top one plays a more critical role in both Rashba effect and spin Hall effect.
基金supported by the National Natural Science Foundation of China(22322304,22273092,22373095)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)+2 种基金the Innovation Program for Quantum Science and Technology(2021ZD0303306)the USTC Tang ScholarThe authors wish to acknowledge the Supercomputing Center of the USTC for providing computational resources.
文摘The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.
基金Project supported by the National Science Foundation of China Higher University(No.10347004)the Science Study Foundation of InnerMongolia(No.NJZY08085)the Science Foundation of Huhhot University of Nationalities(No.HMZZ1201)
文摘The properties of the weakly-coupling bound polaron, considering an influence of Rashba effect, which is brought about by the spin-orbit （SO） interaction, in an semiconductor triangular quantum well （TQW）, have been studied by using the linear combination operator and the unitary transformation methods. We obtain an expression for the ground state energy of the weak-coupling and bound polaron in a TQW as a function of the coupling constant, Coulomb bound potential, and the electron areal density. Our numerical resuks show that the ground state energy of the polaron is composed of four parts, one part is caused by the electrons＇ own energy, the second part is caused by the Rashba effect, the third part occurs because of the Coulomb bound potential, and the last term is induced by the interaction between the electrons and LO phonons. The interactions between the orbit and the spin with different directions have different effects on the ground state energy of the polaron.
文摘Rashba effect in presence of a time-dependent interaction has been considered.Then time-evolution of such a system has been studied by using Lewis–Riesenfeld dynamical invariant and unitary transformation method.So appropriate dynamical invariant and unitary transformation according the considered system have been constructed as well as some special cases have come into this article which are common in physics.
文摘With the support by the National Natural Science Foundation of China,a study by the research group led by Prof.Luo Junwei(骆军委)from the Institute of Semiconductors,Chinese Academy of Sciences discovered a rapid transition of the hole Rashba effect from strong field dependence to saturation
基金supported by the National Natural Science Foundation of China(11725418 and 11334006)the National Basic Research Program of China(2016YFA0301004,2016YFA0301001,and 2015CB921001)+1 种基金Science Challenge Project(TZ2016004)Beijing Advanced Innovation Center for Future Chip(ICFC)
文摘PtTe2 and PtSe2 with trigonal structure have attracted extensive research interests since the discovery of type-II Dirac fermions in the bulk crystals. The evolution of the electronic structure from bulk 3D topological semimetal to 2D atomic thin films is an important scientific question. While a transition from 3D type-II Dirac semimetal in the bulk to 2D semiconductor in monolayer(ML) film has been reported for PtSe2, so far the evolution of electronic structure of atomically thin PtTe2 films still remains unexplored.Here we report a systematic angle-resolved photoemission spectroscopy(ARPES) study of the electronic structure of high quality PtTe2 films grown by molecular beam epitaxy with thickness from 2 ML to 6 ML.ARPES measurements show that PtTe2 films still remain metallic even down to 2 ML thickness, which is in sharp contrast to the semiconducting property of few layer PtSe2 films. Moreover, a transition from 2D metal to 3D type-II Dirac semimetal occurs at film thickness of 4–6 ML. In addition, Spin-ARPES measurements reveal helical spin textures induced by local Rashba effect in the bulk PtTe2 crystal, suggesting that similar hidden spin is also expected in few monolayer PtTe2 films. Our work reveals the transition from2D metal to 3D topological semimetal and provides new opportunities for investigating metallic 2D films with local Rashba effect.
基金Project supported by the Natural Science Foundation of Heilongjiang Province,China (Grant No. F200939)
文摘The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Aharonov-Bohm interferometer are investigated by means of the Green function technique. The periodic Anderson model is used to describe the quantum dot system, the Rashba spin-orbit interaction and the Zeeman splitting under a magnetic field are considered. The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects. We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.
基金Project supported by the National Science Foundation of China (10347004,10747002)Project supported by the National Science Foundation of Hebei(A2008000465463)~~
