Department of Physics, University of California, Berkeley, California 94720, USA.
Phys Rev Lett. 2010 Dec 31;105(26):266806. doi: 10.1103/PhysRevLett.105.266806. Epub 2010 Dec 29.
We investigate the band dispersion and the spin texture of topologically protected surface states in the bulk topological insulators Bi2Se3 and Bi2Te3 by first-principles methods. Strong spin-orbit entanglement in these materials reduces the spin polarization of the surface states to ∼50% in both cases; this reduction is absent in simple models but of important implications to essentially any spintronic application. We propose a way of controlling the magnitude of spin polarization associated with a charge current in thin films of topological insulators by means of an external electric field. The proposed dual-gate device configuration provides new possibilities for electrical control of spin.
我们通过第一性原理方法研究了体拓扑绝缘体 Bi2Se3 和 Bi2Te3 中拓扑保护的表面态的能带色散和自旋织构。这些材料中的强自旋轨道纠缠使两种情况下表面态的自旋极化度降低到 ∼50%；这种降低在简单模型中是不存在的，但对任何自旋电子应用都有重要意义。我们提出了一种通过外加电场控制拓扑绝缘体薄膜中与电荷电流相关的自旋极化强度的方法。所提出的双栅器件结构为电控制自旋提供了新的可能性。
