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Spin pumping through magnetic impurity effect

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Chinese Physics B 2015年第8期24卷 513-516页

作者：邓伟胤盛利邢定钰 National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Collaborative Innovation Center of Advanced Microstructures Nanjing University

We propose a simple adiabatic quantum spin pump to generate pure spin current. The spin pump is driven by an ac gate voltage and a time-dependent magnetic impurity potential. It is found that the total pumped spin per cycle exhibits oscillations, whose magnitude decays exponentially with changing strength of the impurity potential. The proposed method may be useful for spintronic applications.

关键词： pumping pure spin current magnetic impurity

Aharonov-Casher Oscillasions of Transmission Through a Mesoscopic Ring with a magnetic impurity

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Journal of Shanghai University(English Edition) 2004年第1期8卷 38-42页

作者：曹秀凤宋小龙汪源施耀铭 Department of Physics College of Sciences Shanghai University Shanghai 200436 P.R. China

Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated. Both spin-dependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering. It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase. However spin-down transmission and reflection coefficients appear periodic AC oscillations. The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns. In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field.

关键词： mesoscopic AC ring magnetic impurity spin-flipped transmission.

Effect of magnetic-impurity Scattering in Disordered Two-Dimensional Square Lattices Around Half Filling

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Communications in Theoretical Physics 2005年第5X期44卷 929-935页

作者： QIAN Feng YANG Yong-Hong Department of Physics Southeast University Nanjing 210096 China National Laboratory of Solid State Microstructures Nanjing University Nanjing 210008 China

Abstract Weak-localization effect in the presence of magnetic impurities is studied in disordered two-dimensional tight-binding square lattices around half filling. Both the magnetic and nonmagnetic impurities are assumed to be randomly distributed on small fractions of the sites, while the nonmagnetic impurities have a strong potential yielding a unitary-limit scattering. We derive in details the expressions of diffusive π modes in the retarded-retarded （or advanced- advanced） channel, which result from the existence of particle-hole symmetry. The quantum interference correction to the density of states is calculated. While the magnetic-impurity scattering suppresses the quantum correction from π-mode cooperon, it does not affect the contribution of π-mode diffuson.

关键词： weak localization magnetic impurity density of states two-dimensional lattice

Interface chemical states of NiO/NiFe films and their effects on magnetic properties

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Science China(Technological Sciences) 2002年第1期45卷 27-34页

作者：于广华柴春林朱逢吾赖武彦 Department of Materials Physics University of Science and Technology BeijingBeijing 100083China Institute of Physics & Center for Condensed Matter Physics Chinese Academy of SciencesBeijing 100080China

Ta/NiOx/Ni81Fe19/Ta multilayers were prepared by rf reactive and dc magnetron *** exchange coupling field (Hex) and the coercivity (Hc) of NiOx/Ni81Fe19 as a function of the ratio of Ar to O2 during the deposition process were *** composition and chemical states at the interface region of NiOx/NiFe were also investigated using the X-ray photoelectron spectroscopy (XPS) and peak decomposition *** results show that the ratio of Ar to O2 has great effect on the nickel chemical states in NiOx *** the ratio of Ar to O2 is equal to 7 and the argon sputtering pressure is 0.57 Pa,the x value is approximately 1 and the valence of nickel is +*** this point,NiOx is antiferromagnetic NiO and the corresponding Hex is the *** the ratio of Ar/O2 deviates from 7,the exchange coupling field (Hex) will decrease due to the presence of magnetic impurities such as Ni+3 or metallic Ni at the interface region of NiOx/NiFe,while the coercivity (Hc) will increase due to the metallic *** studies also show that there are two thermodynamically favorable reactions at the NiO/NiFe interface: NiO+Fe=Ni+FeO and 3NiO+2Fe=3Ni+*** interface reaction products are magnetic impurities at the interface region of NiO/*** is believed that these magnetic impurities would have effect on the exchange coupling field (Hex) and the coercivity (Hc) of NiO/NiFe.

关键词： NiO x magnetic impurity exchange coupling field (H ex) coercivity (H c) X-ray photoelectron spectroscopy (XPS)

Entanglement in One-Dimensional Random XY Spin Chain with Dzyaloshinskii-Moriya Interaction

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Chinese Physics Letters 2008年第3期25卷 817-820页

作者：单传家程维文刘堂昆黄燕霞李宏 Department of Physics Hubei Normal University Huangshi 435002

The impurities of exchange couplings, external magnetic fields and Dzyaloshinskii-Moriya （DM） interaction considered as Gaussian distribution, and the entanglement in one-dimensional random XY spin systems is investigated by the method of solving the different spin-spin correlation functions and the average magnetization per spin. The entanglement dynamics at central locations of ferromagnetic and antiferromagnetic chains have been studied by varying the three impurities and the strength of DM interaction. （i） For the ferromagnetic spin chain, the weak DM interaction can improve the amount of entanglement to a large value, and the impurities have the opposite effect on the entanglement below and above critical DM interaction. （ii） For the antiferromagnetic spin chain, DM interaction can enhance the entanglement to a steady value. Our results imply that DM interaction strength, the impurity and exchange couplings （or magnetic field） play competing roles in enhancing quantum entanglement.

关键词： PAIRWISE ENTANGLEMENT magnetic impurity 2 ATOMS STATE SYSTEMS MODEL

Quasi-one-dimensional characters in topological semimetal TaNiTe_(5)

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Chinese Physics B 2023年第5期32卷 586-590页

作者：马妮王德阳黄本锐李凯仪宋靖鹏刘建忠梅红萍叶茂李昂 State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

One-dimensional(1D)topological insulators are superior for low-dissipation applications owing to the 1D character of surface states where scatterings other than prohibited backscattering are further *** the proposed candidates for 1D topological materials,TaNiTe_(5)has attracted intensive attention for its quasi-one-dimensional(quasi-1D)crystalline *** this study,we identify the chain-like construction and anisotropic electronic states on TaNiTe_5 surface with scanning tunneling *** electron scatterings are largely suppressed even with chromium impurities deposited on the surface and magnetic field applied normal to the surface,which endows TaNiTe_5 great potential for low-dissipation spintronic applications.

关键词： quasi-one-dimensional magnetic impurity scanning tunneling microscopy

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电子非厄米系统中的拓扑自旋图样

Science Bulletin 2024年第3期69卷 325-333页

作者：张骁骁 Naoto Nagaosa RIKEN Center for Emergent Matter Science(CEMS) WakoSaitama 351-0198Japan Department of Applied Physics University of TokyoTokyo 113-8656Japan

Non-Hermitian systems have been discussed mostly in the context of open systems and *** experimental progress is much from optical,cold-atomic,and classical platforms due to the vast tunability and clear identification of ***,their counterpart in solid-state electronic systems in equilibrium remains unmasked although highly desired,where a variety of materials are available,calculations are solidly founded,and accurate spectroscopic techniques can be *** demonstrate that,in the surface state of a topological insulator with spin-dependent relaxation due to magnetic impurities,highly nontrivial topological soliton spin textures appear in momentum *** spin-channel phenomena are delicately related to the type of non-Hermiticity and correctly reveal the most robust non-Hermitian features detectable ***,the distinct topological soliton objects can be deformed to each other,mediated by topological transitions driven by tuning across a critical direction of doped *** results not only open a solid-state avenue to exotic spin patterns via spin-and angle-resolved photoemission spectroscopy,but also inspire non-Hermitian dissipation engineering of spins in solids.

关键词： Non-Hermitian system Topological spin texture magnetic impurity Surface state ARPES

Kondo Effect of Cobalt Adatoms on a Graphene Monolayer Controlled by Substrate-Induced Ripples

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Kondo Effect of Cobalt Adatoms on a Graphene Monolayer Contr...