共查询到19条相似文献,搜索用时 109 毫秒
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一种输出自旋流的装置--自旋池 总被引:1,自引:0,他引:1
文章作者设计了一种能够给未来的自旋电路提供驱动自旋流的动力装置,即自旋池.该自旋池有如下四个基本特点:(1)有两个极能使自旋流从一个极流入,从另一个极流出,从而建立一个闭合的自旋回路;(2)有一个能量源;(3)能保持自旋相干;(4)能输出不附加任何净电荷流的纯自旋流,值得注意的是,该自旋池能通过现有的技术手段实现。 相似文献
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自旋流的产生和测量是自旋电子学面临的重大挑战.逆自旋霍尔效应提供了对自旋流进行电学测量的有效手段.文章总结了近年来人们对金属薄膜中的逆自旋霍尔效应的研究,从非局域电注入、铁磁共振注入、声波共振注入和圆偏振光注入这四种不同的自旋流注入方式来介绍逆自旋霍尔效应的物理机制、实现方式和影响因素. 相似文献
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作为自旋电子学的重要研究内容,如何在固态系统中产生、操控以及探测自旋流引起了研究人员的广泛兴趣。基于自旋轨道耦合的自旋霍尔效应为在非磁性半导体中产生自旋流提供了一种有效途径。然而,在具有自旋轨道耦合的系统中,自旋流并不守恒。如何理解这点并恰当地表述相应的连续性方程,成为自旋输运研究的基本问题之一。本文主要综述自旋轨道耦合系统中自旋流与自旋霍尔效应方面的研究进展。引入SU(2)规范势后,自旋流满足协变形式的连续性方程,该方程保证了SU(2)Kubo公式在不同规范固定下的自洽性。利用SU(2)场强张量,可以直接得到自旋密度和自旋流在SU(2)外场中受到的自旋力,该力在只有U(1)磁场时对应于Stern-Gerlach力。由于依赖杂质散射的外在自旋霍尔效应很难被利用,内在自旋霍尔效应的概念被提出:在非磁半导体中,U(1)电场会诱导出自旋流并导致系统边缘处的自旋积累。自旋霍尔效应已经在半导体和金属材料中被观察到。虽然在干净的二维电子气中自旋霍尔电导率是一普适常数e/8π,但杂质对它的影响却引起了人们的高度关注。通过引入退相干效应,自旋霍尔效应中杂质效应的一些令人困惑的理论结果,则得到清晰的解释。此外,本文还将介绍具有层间隧穿的双层二维电子气中的自旋输运现象。在能量简并点附近,自旋霍尔电导率和隧穿自旋电导率均会出现共振现象。当两层间的杂质势强度存在差异时,隧穿自旋电导率随门压的变化曲线呈现出非对称性,显示出自旋二极管效应。 相似文献
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自旋轨道耦合系统中的自旋流与自旋霍尔效应 总被引:2,自引:0,他引:2
作为自旋电子学的重要研究内容,如何在固态系统中产生、操控以及探测自旋流引起了研究人员的广泛兴趣.基于自旋轨道耦合的自旋霍尔效应为在非磁性半导体中产生自旋流提供了一种有效途径.然而,在具有自旋轨道耦合的系统中,自旋流并不守恒.如何理解这点并恰当地表述相应的连续性方程,成为自旋输运研究的基本问题之一.本文主要综述自旋轨道耦合系统中自旋流与自旋霍尔效应方面的研究进展.引入SU(2)规范势后,自旋流满足协变形式的连续性方程,该方程保证了SU(2)Kubo公式在不同规范固定下的自洽性.利用SU(2)场强张量,可以直接得到自旋密度和自旋流在SU(2)外场中受到的白旋力,该力在只有U(1)磁场时对应于Stern-Gerlach力.由于依赖杂质散射的外在自旋霍尔效应很难被利用,内在自旋霍尔效应的概念被提出:在非磁半导体中,U(1)电场会诱导出自旋流并导致系统边缘处的自旋积累.自旋霍尔效应已经在半导体和金属材料中被观察到.虽然在干净的二维电子气中自旋霍尔电导率是一普适常数e/8π,但杂质对它的影响却引起了人们的高度关注.通过引入退相干效应,自旋霍尔效应中杂质效应的一些令人困惑的理论结果,则得到清晰的解释.此外,本文还将介绍具有层间隧穿的双层二维电子气中的自旋输运现象.在能量简并点附近,自旋霍尔电导率和隧穿白旋电导率均会出现共振现象.当两层间的杂质势强度存在差异时,隧穿自旋电导率随门压的变化曲线呈现出非对称性,显示出自旋二极管效应. 相似文献
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自旋流的产生和测量是自旋电子学面临的重大挑战.逆自旋霍尔效应提供了对自旋流进行电学测量的有效手段.文章总结了近年来人们对金属薄膜中的逆自旋霍尔效应的研究,从非局域电注入、铁磁共振注入、声波共振注入和圆偏振光注入这四种不同的自旋流注入方式来介绍逆自旋霍尔效应的物理机制、实现方式和影响因素. 相似文献
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对《大学物理》2000年第11期上发表的《氢原子的磁矩-对自旋的讨论之一》一提出了不同的看法,认为该错把相对论的流密度当成了非相对论的流密度,前不能在非相对论近似下过滤到后,在相对论情况下,自旋和轨道耦合在一起,不能互相独立,在非相对论情况下自旋独立于轨道运动而存在;因而,自旋不是轨道角动量的相对论效应。 相似文献
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Spin current and its heat effect in a multichannel quantum wire with Rashba spinben orbit coupling 下载免费PDF全文
Using the perturbation method, we theoretically study the spin current and its heat effect in a multichannel quantum wire with Rashba spin—orbit coupling. The heat generated by the spin current is calculated. With the increase of the width of the quantum wire, the spin current and the heat generated both exhibit period oscillations with equal amplitudes. When the quantum-channel number is doubled, the oscillation periods of the spin current and of the heat generated both decrease by a factor of 2. For the spin current js,xy, the amplitude increases with the decrease of the quantum channel; while the amplitude of the spin current js,yx remains the same. Therefore we conclude that the effect of the quantum-channel number on the spin current js,xy is greater than that on the spin current js,yx. The strength of the Rashba spin—orbit coupling is tunable by the gate voltage, and the gate voltage can be varied experimentally, which implies a new method of detecting the spin current. In addition, we can control the amplitude and the oscillation period of the spin current by controlling the number of the quantum channels. All these characteristics of the spin current will be very important for detecting and controlling the spin current, and especially for designing new spintronic devices in the future. 相似文献
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J.-P. Wang H. Meng 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,59(4):471-474
Spin torque transfer structures with new spin switching configurations are
proposed, fabricated and investigated in this paper. The non-uniform
current-induced magnetization switching is implemented based on both GMR and
MTJ nano devices. The proposed new spin transfer structure has a hybrid free
layer that consists of a layer with conductive channels (magnetic) and
non-conductive matrix (non-magnetic) and traditional free layer(s). Two
mechanisms, a higher local current density by nano-current-channels and a
non-uniform magnetization switching (reversal domain nucleation and growth)
by a magnetic nanocomposite structure, contribute in reducing the switching
current density. The critical switching current density for the new spin
transfer structure is reduced to one third of the typical value for the
normal structure. It can be expected to have one order of magnitude or more
reduction for the critical current density if the optimization of materials
and fabrication processes could be done further. Meanwhile, the thermal
stability of this new spin transfer structure is not degraded, which may
solve the long-standing scaling problem for magnetic random access memory
(MRAM). This spin transfer structure, with the proposed and demonstrated new
spin switching configurations, not only provides a solid approach for the
practical application of spin transfer devices but also forms a unique
platform for researchers to explore the non-uniform current-induced
switching process. 相似文献
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He XW Shen B Chen YH Zhang Q Han K Yin CM Tang N Xu FJ Tang CG Yang ZJ Qin ZX Zhang GY Wang ZG 《Physical review letters》2008,101(14):147402
Under normal incidence of circularly polarized light at room temperature, a charge current with swirly distribution has been observed in the two-dimensional electron gas in Al{0.25}Ga{0.75}N/GaN heterostructures. We believe that this anomalous charge current is produced by a radial spin current via the reciprocal spin Hall effect. It suggests a new way to research the reciprocal spin Hall effect and spin current on the macroscopic scale and at room temperature. 相似文献
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We consider a quantum dot attached to leads in the Coulomb blockade regime that has a spin 1 / 2 ground state. We show that, by applying an ESR field to the dot spin, the stationary current in the sequential tunneling regime exhibits a new resonance peak whose linewidth is determined by the single spin decoherence time T2. The Rabi oscillations of the dot spin are shown to induce coherent current oscillations from which T2 can be deduced in the time domain. We describe a spin inverter which can be used to pump current through a double dot via spin flips generated by ESR. 相似文献
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We report a theoretic study on modulating the spin polarization of charge current in a mesoscopic four-terminal device of cross structure by using the inverse spin hall effect. The scattering region of device is a two-dimensional electron gas (2DEG) with Rashba spin orbital interaction (RSOI), one of lead is ferromagnetic metal and other three leads are spin-degenerate normal metals. By using Landauer-Büttiker formalism, we found that when alongitudinal charge current flows through 2DEG scattering region from FM lead by external bias, the transverse current can be either a pure spin current or full-polarized charge current due to the combined effect of spin hall effect and its inverse process, and the polarization of this transverse current can be easily controlled by several device parameters such as the Fermi energy, ferromagnetic magnetization, and the RSOI constant. Our method may pave a new way to control the spin polarization of a charge current. 相似文献
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We present a new device which consists of a molecular quantum dot (MQD) attached to a normal-metal, two ferromagnetic (FM), and a superconducting leads. The spin-related Andreev reflection (AR) current and the spin-dependent single-particle tunneling current through the normal-metal terminal are obtained, and it is found that the spin current exhibits the transistor-like behavior. The joint effects of the coherent spin flip and the angle between magnetic moments of the two FM leads on the spin current are also studied, these results provide the possibility to manipulate the spin current with the system parameters. 相似文献
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《中国物理快报》2016,(4)
We theoretically study the spin transport through a two-terminal quantum dot device under the influence of a symmetric spin bias and circularly polarized light.It is found that the combination of the circularly polarized light and the applied spin bias can result in a net charge current.The resultant charge current is large enough to be measured when properly choosing the system parameters.The resultant charge current can be used to deduce the spin bias due to the fact that there exists a simple linear relation between them.When the external circuit is open,a charge bias instead of a charge current can be induced,which is also measurable by present technologies.These findings indicate a new approach to detect the spin bias by using circularly polarized light. 相似文献