Key Laboratory of Semiconductor Material Science, Institute of Semiconductors, Chinese Academy of Science, PO Box 912, Beijing 100083, People's Republic of China.
J Phys Condens Matter. 2011 Jan 12;23(1):015801. doi: 10.1088/0953-8984/23/1/015801. Epub 2010 Dec 6.
We theoretically study the electronic structure, spin splitting, effective mass, and spin orientation of InAs nanowires with cylindrical symmetry in the presence of an external electric field and uniaxial stress. Using an eight-band k·p theoretical model, we deduce a formula for the spin splitting in the system, indicating that the spin splitting under uniaxial stress is a nonlinear function of the momentum and the electric field. The spin splitting can be described by a linear Rashba model when the wavevector and the electric field are sufficiently small. Our numeric results show that the uniaxial stress can modulate the spin splitting. With the increase of wavevector, the uniaxial tensile stress first restrains and then amplifies the spin splitting of the lowest electron state compared to the no strain case. The reverse is true under a compression. Moreover, strong spin splitting can be induced by compression when the top of the valence band is close to the bottom of the conductance band, and the spin orientations of the electron stay almost unchanged before the overlap of the two bands.
我们从理论上研究了在外部电场和单轴应力存在下具有圆柱对称性的 InAs 纳米线的电子结构、自旋劈裂、有效质量和自旋取向。我们利用八带 k·p 理论模型推导出了该体系中自旋劈裂的公式，表明单轴应力下的自旋劈裂是动量和电场的非线性函数。当波矢和电场足够小时，自旋劈裂可以用线性 Rashba 模型来描述。我们的数值结果表明，单轴应力可以调制自旋劈裂。随着波矢的增加，与无应变情况相比，单轴拉伸应力最初会抑制，然后放大最低电子态的自旋劈裂。在压缩下则相反。此外，当价带顶接近电导带底时，压缩会产生强烈的自旋劈裂，并且在两个能带重叠之前，电子的自旋取向几乎保持不变。
