铁磁、肖特基金属和半导体纳米自旋过滤器中的量子尺寸效应

Quantum size effect and voltage-tunable spin polarization in an electron-spin filter based on hybrid ferromagnetic-Schottkymetal and semiconductor nanostructure

采用转移矩阵法,研究了结构尺度对自旋过滤器中电子自旋极化特性的影响.该自旋过滤器可以通过在半导体异质结上沉积纳米尺度的铁磁条带和肖特基金属条带来实现.计算结果表明,电子的自旋极化特性强烈依赖于铁磁条带和肖特基金属条带的结构尺度和位置,即该器件中存在量子尺寸效应.此外,我们的计算结果还表明,电子的自旋极化特性还与施加在肖特基金属条上的电压所诱发的电垒高度密切相关.因此,我们可以通过改变施加在肖特基金属条上的电压来调控该器件中电子的自旋极化特性,制造一个电压可调的电子自旋过滤器.

Based on transfer-matrix method, the effect of structural size scale on electron-spin polariza- tion in a spin filter has been studied. The spin filter can be realized by depositing nanosized ferromagnet- ic metal stripe and Schottky normal metal stripe on the top of the semiconductor heterostructure. It is shown that the electron-spin polarization is dependent greatly on the sizes and the position of the stripes. Thus, a quantum size effect exists in this device and the optimal spin polarization can be achieved by fe- licitously fabricating the stripes. It also is shown that the spin polarization can be altered by adjusting the electric-barrier height induced by an applied voltage to the Schottky normal metal stripe, which can result in a voltage-tunable spin filter.