GaMnAs/AlAs/GaAs/AlAs/GaMnAs隧道结的磁致电阻效应

Magnetoresistance Effect of GaMnAs/AlAs/GaAs/AlAs/GaMnAs Tunnel Junctions

利用k·p微扰和多能带量子传输边界相结合,推导出自旋空间中的量子坐标轴变换矩阵,以及空穴透过GaMnAs/AlAs/GaMnAs/AlAs/GaMnAs双势垒铁磁半导体(FS)隧道结的透射系数和磁致电阻(TMR)理论公式.计算了重空穴和轻空穴透射系数随入射能量的变化,得到TMR与两层FS磁化方向夹角(θ)的关系.研究发现透射系数随着入射能量递增出现明显震荡,相对于非磁性半导体,轻空穴和重空穴透射系数的差值减小;与单势垒隧道结不同,双势垒隧道结中TMR和sin^(2)(θ/2)之间呈现出非线性关系.其结果对磁性半导体隧道结的研究具有一定的参考价值.

In this paper,the k·pmodel combined with the multiband quantum transmitting boundary method was applied to calculate the transfer-matrix of spin-polarized resonant in the spin space,and the transmission coefficient of the tunnel junction and the theoretical formula of magnetoresistance(TMR)of GaMnAs/AlAs/GaMnAs/AlAs/GaMnAs double barrier FS tunnel junction transmitted by holes are obtained.The relationship between the transmission coefficient and the incident energy was calculated for heavy and light holes.The relationship between TMR and the arbitrary angleθbetween the magnetic direction of two FS was obtained.It was shown that the transmission coefficient exhibits significant oscillation with increasing incident energy,and the difference of transmission coefficients between light and heavy holes decreases with respect to the non-magnetic semiconductor.Unlike the single barrier tunnel junction,the TMR in the double barrier tunnel junction was linearly uncorrelated with sin^(2)(θ/2).This work will provide a reference for studying tunnel junctions of magnetic semiconductor.