含stubs量子波导系统的电子自旋极化输运性质  

Spin-polarized transport in quantum waveguide systems with attached stubs

作　　者：肖贤波[1,2] 李小毛[2] 陈宇光[1] 

机构地区：[1]同济大学物理系,上海200092 [2]江西农业大学理学院,南昌330045

出　　处：《物理学报》2009年第11期7909-7913,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10774112);江西农业大学青年科学基金(批准号:2219)资助的课题~~

摘　　要：理论上研究了含stubs的Rashba自旋轨道耦合(spin-orbit coupling,SOC)量子波导系统的自旋极化输运性质.利用晶格格林函数方法,发现由于stubs和SOC产生的势阱使系统中出现束缚态,这些束缚态与传播态之间相互干涉导致电导中出现Fano共振结构,同时在对应的自旋极化率中也出现Fano共振或反共振结构.此外,由于系统结构的突变使电子被反向散射和量子干涉效应,电导中出现一系列的共振峰.但是,当系统加上外磁场后,所有这些效应都被抑制,系统重新出现量子化电导,同时自旋电导也出现台阶结构.其物理根源是因为磁场相当于增加了一个横向限制势而使子带间的干涉效应变弱.We theoretically studied the spin-polarized electron transport properties of quantum waveguide systems with attached stubs in the presence of Rashba spin-orbit coupling （SOC） by the lattice Green function approach. It is shown that the structure-induced Fano resonance and SOC-induced Fano resonance exist in the charge conductance in consequence of the bound states interfering with the conductance states. At the same time, the Fano resonance and antiresonance structures are also found in the spin polarization. In addition, due to the effect of quantum interference and backscattering caused by abrupt change of quantum wire width, a series of resonant peaks and dips appear in the charge conductance and spin conductance. However, all these effects are suppressed and quantization plateau is recovered in the charge conductance and spin conductance when applying a magnetic field to the system. The underlying physics is that the effect of the magnetic field is equivalent to the enhancement of the lateral confining potential, which reduces the intersubband mixing.

关 键 词：量子波导 自旋极化输运 自旋轨道耦合 

分 类 号：O471.1[理学—半导体物理]