PbTe/PbSrTe半导体非对称量子阱中的Rashba效应

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Pb_1-ySr_yTe/PbTe/Pb_1-xSr_xTe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 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

Rashba effect in PbTe/PbSrTe asymmetric quantum wells

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 multivalley and anisotropic band structures. In this work， we calculated Rashba splitting in Pb_1-ySr_yTe/PbTe/Pb_1-xSr_xTe asymmetric QWs with growth orientations ［100］， ［110］ and ［111］. The results show that Rashba splitting reaches the maximum of 2.2meV when the well width of PbTe QWs with growth orientation ［100］ is 5.0nm， 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.