According to the general principle of non-equilibrium thermodynamics, we propose a set of macroscopic transport equations for the spin transport and the charge transport, In particular, the spin torque is introduced a...According to the general principle of non-equilibrium thermodynamics, we propose a set of macroscopic transport equations for the spin transport and the charge transport, In particular, the spin torque is introduced as a generalized ＇current density＇ to describe the phenomena associated with the spin non-conservation in a unified framework. The Einstein relations and the Onsager relations between different transport phenomena are established. Specifically, the spin transport properties of the isotropic non-magnetic and the isotropic magnetic two-dimensional electron gases are fully described by using this theory, in which only the macroscopic-spin-related transport phenomena allowed by the symmetry of the system are taken into account.展开更多
Based on the principle of general relativity,geometrization of interaction,the interaction of the inhomogeneous isotropic medium to light can be equated to a non-Euclidean geometry field just like the situation of gra...Based on the principle of general relativity,geometrization of interaction,the interaction of the inhomogeneous isotropic medium to light can be equated to a non-Euclidean geometry field just like the situation of gravity,i.e.,light travels in the null geodesic in the non-Euclidean curved space-time,which is equivalent to the Fermat principle for the inhomogeneous media.In this paper,the propagation of light in an inhomogeneous media is studied by means of the effective metric theory.The modification to the classical ray equation of photons is derived from the geodesic equation of photon by considering the spin effect of photons,which is induced via the spin-orbit coupling of photons,and the corresponding Hamiltonian of photonis proposed.Based on the spin-orbit coupling of photon,a light splitting phenomenon emerges in the inhomogeneous media,which is the spin hall effect of photon.展开更多
For the spin Hall effect arising from strong band-structure spin-orbit coupling, a semiclassical Boltz- mann theory reasonably addressing the intriguing disorder effect called side-jump has not yet been developed. Thi...For the spin Hall effect arising from strong band-structure spin-orbit coupling, a semiclassical Boltz- mann theory reasonably addressing the intriguing disorder effect called side-jump has not yet been developed. This paper describes such a theory in which the key ingredient is the spin-current counter- part of the semiclassical side-jump velocity （introduced in the context of the anomalous Hall effect）. Applying this theory to spin Hall effects in a two-dimensional electron gas with giant Rashba spin-orbit coupling, largely enhanced spin Hall angle is found in the presence of magnetic impurities when only the lower Rashba band is partially occupied.展开更多
Magnetic tunnel junctions(MTJs)switched by spin-orbit torque(SOT)have attracted substantial interest owing to their advantages of ultrahigh speed and prolonged endurance.Both field-free magnetization switching and hig...Magnetic tunnel junctions(MTJs)switched by spin-orbit torque(SOT)have attracted substantial interest owing to their advantages of ultrahigh speed and prolonged endurance.Both field-free magnetization switching and high tunneling magnetoresistance(TMR)are critical for the practical application of SOT magnetic random access memory(MRAM).In this work,we propose an MTJ structure based on an iridium(Ir)bottom layer.Ir metal is a desirable candidate for field-free SOT switching owing to its strong intrinsic spin Hall conductivity(SHC),which can be enhanced via doping.Herein,we study TMR in Ir-based MTJs with symmetric and asymmetric structures.Ir-based MTJs exhibit large TMR,which can be further enhanced by heavy metal symmetry owing to the resonant tunneling effect.Our comprehensive investigations illustrate that Ir-based MTJs are promising candidates for realizing SOT switching and high TMR.展开更多
基金Project supported by the National Key Basic Research Special Foundation of China (Grant No 2006CB921300)the National Natural Science Foundation of China (Grant No 10604063)
文摘According to the general principle of non-equilibrium thermodynamics, we propose a set of macroscopic transport equations for the spin transport and the charge transport, In particular, the spin torque is introduced as a generalized ＇current density＇ to describe the phenomena associated with the spin non-conservation in a unified framework. The Einstein relations and the Onsager relations between different transport phenomena are established. Specifically, the spin transport properties of the isotropic non-magnetic and the isotropic magnetic two-dimensional electron gases are fully described by using this theory, in which only the macroscopic-spin-related transport phenomena allowed by the symmetry of the system are taken into account.
基金Project supported by the Natural Science Foundation of Shanghai (Grant No.09ZR1410900)the Shanghai Leading Academic Discipline Project (Grant No.S30105)
文摘Based on the principle of general relativity,geometrization of interaction,the interaction of the inhomogeneous isotropic medium to light can be equated to a non-Euclidean geometry field just like the situation of gravity,i.e.,light travels in the null geodesic in the non-Euclidean curved space-time,which is equivalent to the Fermat principle for the inhomogeneous media.In this paper,the propagation of light in an inhomogeneous media is studied by means of the effective metric theory.The modification to the classical ray equation of photons is derived from the geodesic equation of photon by considering the spin effect of photons,which is induced via the spin-orbit coupling of photons,and the corresponding Hamiltonian of photonis proposed.Based on the spin-orbit coupling of photon,a light splitting phenomenon emerges in the inhomogeneous media,which is the spin hall effect of photon.
文摘For the spin Hall effect arising from strong band-structure spin-orbit coupling, a semiclassical Boltz- mann theory reasonably addressing the intriguing disorder effect called side-jump has not yet been developed. This paper describes such a theory in which the key ingredient is the spin-current counter- part of the semiclassical side-jump velocity （introduced in the context of the anomalous Hall effect）. Applying this theory to spin Hall effects in a two-dimensional electron gas with giant Rashba spin-orbit coupling, largely enhanced spin Hall angle is found in the presence of magnetic impurities when only the lower Rashba band is partially occupied.
基金supported by the National Natural Science Foundation of China(Grant Nos.61627813,and 61571023)the International Collaboration Project B16001,and the National Key Technology Program of China(Grant No.2017ZX01032101)supported by the Academic Excellence Foundation of BUAA for PhD Students
文摘Magnetic tunnel junctions(MTJs)switched by spin-orbit torque(SOT)have attracted substantial interest owing to their advantages of ultrahigh speed and prolonged endurance.Both field-free magnetization switching and high tunneling magnetoresistance(TMR)are critical for the practical application of SOT magnetic random access memory(MRAM).In this work,we propose an MTJ structure based on an iridium(Ir)bottom layer.Ir metal is a desirable candidate for field-free SOT switching owing to its strong intrinsic spin Hall conductivity(SHC),which can be enhanced via doping.Herein,we study TMR in Ir-based MTJs with symmetric and asymmetric structures.Ir-based MTJs exhibit large TMR,which can be further enhanced by heavy metal symmetry owing to the resonant tunneling effect.Our comprehensive investigations illustrate that Ir-based MTJs are promising candidates for realizing SOT switching and high TMR.
