PbTe／PbSrTe半导体非对称量子阱中的Rashba效应  

Rashba effect in PbTe/PbSrTe asymmetric quantum wells

作　　者：徐天宁[1,2] 吴惠桢[1] 隋成华[2] 

机构地区：[1]浙江大学物理系,杭州310027 [2]浙江工业大学之江学院理学系,杭州310024

出　　处：《物理学报》2008年第12期7865-7871,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10434090);教育部博士点基金(批准号20060335035)资助的课题~~

摘　　要：窄带隙半导体异质结构的自旋效应最近受到了国际上的很大关注.Ⅳ-Ⅵ族半导体具有各向异性和多能谷的特征,因此可以预期Rashba自旋效应在不同取向的Ⅳ-Ⅵ族半导体量子阱结构中存在显著差异.计算了多个取向的Pb1-y SryTe/PbTe/Pb1-x SrxTe非对称量子阱中的Rashba分裂能,结果表明[100]取向的PbTe量子阱的Rashba分裂能在阱宽为5.0nm时高达2.2meV,而沿其他两个主要方向([110],[111])生长的量子阱由于能谷的退简并存在两组Rashba分裂能.给出了Rashba自旋分裂能与量子阱非对称参量、阱宽、温度和波矢k∥的依赖关系.Ⅳ-Ⅵ族半导体非对称量子阱结构比Ⅲ-Ⅴ族半导体具有更大的Rashba自旋分裂能,这一特点使得它在自旋电子器件领域可能具有潜在的应用价值.Recently, spin effect in narrow gap semiconductor heterostructures has attracted much attention. However, Rashba spin effect is quite different in Ⅳ-Ⅵ asymmetric quantum wells （QWs） with various growth orientations due to their muhivalley and anisotropic band structures. In this work, we calculated Rashba splitting in Pb1-y Sry Te/PbTe/Pb1 - x Srx Te asymmetric QWs with growth orientations [ 100], [ 110] and [ 111 ]. The results show that Rashba splitting reaches the maximum of 2.2 meV when the well width of PbTe QWs with growth orientation [ 100] is 5.0 nm, and two groups of Rashba splitting is obtained in PbTe and QWs with growth orientations [ 110] and [ 111 ], respectively, because the quantum confinement lifts off the fourfold degeneracy of the L-energy valleys. The dependences of Rashba splitting on asymmetry of QWs, well width, temperature and k//（the wave vactor in the plane） are also investigated. Large Rashba spin splitting may make Ⅳ-Ⅵ asymmetric QWs as a material candidate for spintronic devices.

关 键 词：Ⅳ-Ⅵ族半导体 非对称量子阱 Rashba效应 自旋-轨道耦合分裂 

分 类 号：O471.1[理学—半导体物理]