Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
Phys Rev Lett. 2012 Mar 16;108(11):117403. doi: 10.1103/PhysRevLett.108.117403. Epub 2012 Mar 14.
Using femtosecond time- and angle-resolved photoemission spectroscopy, we investigated the nonequilibrium dynamics of the topological insulator Bi2Se3. We studied p-type Bi2Se3, in which the metallic Dirac surface state and bulk conduction bands are unoccupied. Optical excitation leads to a metastable population at the bulk conduction band edge, which feeds a nonequilibrium population of the surface state persisting for >10 ps. This unusually long-lived population of a metallic Dirac surface state with spin texture may present a channel in which to drive transient spin-polarized currents.
使用飞秒时间分辨和角度分辨光电子能谱，我们研究了拓扑绝缘体 Bi2Se3 的非平衡动力学。我们研究了 p 型 Bi2Se3，其中金属狄拉克表面态和体导带是空的。光激发导致体导带边缘的亚稳态粒子数增加，从而产生持续超过 10 ps 的表面态的非平衡粒子数。这种具有自旋结构的金属狄拉克表面态的异常长寿命粒子数可能提供了一个驱动瞬态自旋极化电流的通道。
