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Spin Polarization and Andreev Conductance through a Diluted Magnetic Semiconductor Quantum Wire with Spin--Orbit Interaction 下载免费PDF全文
Spin-dependent Andreev reflection and spin polarization through a diluted magnetic semiconductor quantum wire coupled to normal metallic and superconductor electrodes are investigated using scattering theory. When the spin-orbit coupling is considered, more Andreev conductance steps appear at the same Fermi energy. Magnetic semiconductor quantum wire separates the spin-up and spin-down electrons. The Fermi energy, at which different- spin-state electrons begin to separate, becomes lower due to the effect of the spin-orbit interaction. The spin filter effect can be measured more easily by investigating the Andreev conductance than by investigating the normal conductance. 相似文献
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Using the tight-binding model approximation, this paper investigates theoretically spin-dependent quantum transport through an Aharonov-Bohm (AB) interferometer. An external magnetic field is applied to produce the spinpolarization and spin current. The AB interferometer, acting as a spin splitter, separates the opposite spin polarization current. By adjusting the energy and the direction of the magnetic field, large spin-polarized current can be obtained. 相似文献
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A spin device with three normal metal leads via triple quantum dot in the presence of Rashba spin-orbit interaction is proposed, which is free from magnetic field or magnetic material. Using nonequilibrium Green's function technique, we investigate the spin current through the three-quantum-dot device. It is found that the spin current can be affected by the strength of the Rashba spin-orbit interaction, Coulomb interaction, the energy of the quantum dot and the bias voltage of the lead. The periodic oscillation of spin current can be controlled by tuning the Rashba spin-orbit interaction. 相似文献
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研究了含δ势垒的铁磁/半导体/铁磁异质结中自旋相关的透射概率和渡越时间,讨论了量子尺寸效应和Rashba自旋轨道耦合效应对隧穿特性的影响.研究结果表明:δ势垒的存在降低了自旋电子的透射概率,改变了透射概率的位相.Rashba自旋轨道耦合强度的增加加大了透射概率的振荡频率.不同自旋取向的电子隧穿异质结时,渡越时间随着半导体长度、Rashba自旋轨道耦合强度以及两铁磁电极中的磁化方向的夹角的变化而变化.
关键词:
δ势垒')" href="#">δ势垒
铁磁/半导体/铁磁异质结
Rashba自旋轨道耦合效应
渡越时间 相似文献
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The effect of the ferromagnetic metal layer on tunnelling conductance and magnetoresistance in double magnetic planar junctioins 下载免费PDF全文
Based on the free-electron approximation,we investigate the effect of the ferromagnetic metal layer on the tunnelling magnetoresistance(TMR) and tunnelling conductance(TC)in the double magnetic tunnel junctions(DMTJs) of the structure NM/FM/I(S)/NM/I(S)/FM/NM,where FM,NM and I(S) represent the ferromagnetic metal,nonmagetic metal and insulator(Semiconductor),respectively,The FM,I(S)and inner NM layers are of finite thickness,while the thickness of the outer NM layer is infinite.The calculated results show that,due to the spin-dependent interfacial potential barriers caused by electronic band mismatch between the various magnetic and nonmagnetic layers,the dependences of the TMR and TC on the thicknesses of the FM layers exhibit oscillations,and a much higher TMR can be obtained for suitable thicknesses of FM layers. 相似文献
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研究了连接在正常金属电极和超导电极之间的耦合Majorana束缚态(MBSs)T形双量子点结构中的Andreev反射.研究发现,对于T形双量子点结构,当入射能量等于边耦合量子点能级时Andreev反射电导出现Fano振荡,连接MBSs之后,零费米能附近出现一对新的Fano型振荡峰.如果忽略两个MBSs之间的相互作用,零费米能点的Andreev反射电导为定值1/2G_0(G_0=2e~2/h),不受量子点能级、双量子点之间耦合强度以及量子点与MBSs之间的耦合强度的影响.此外,在没有耦合MBSs的T形双量子点结构中,调节双量子点间的耦合强度可以使零费米能附近的Andreev反射电导出现由共振带向反共振带的转变,而耦合MBSs之后,又可以使反共振消失转而出现新的共振峰. 相似文献
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We study electrons tunneling through a double-magnetic-barrier structure on the surface of monolayer graphene.The transmission probability and the conductance are calculated by using the transfer matrix method.The results show that the normal incident transmission probability is blocked by the magnetic vector potential and the Klein tunneling region depends strongly on the direction of the incidence electron.The transmission probability and the conductance can be modulated by changing structural parameters of the barrier,such as width and height,offering a possibility to control electron beams on graphene. 相似文献
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