Topological insulators represent a new quantum state of matter that are insulating in the bulk but metallic on the edge or surface. In the Dirac surface state, it is well-established that the electron spin is locked with the crystal momentum. Here we report a new phenomenon of the spin texture locking with the orbital texture in a topological insulator Bi2Se3. We observe light-polarization-dependent spin texture of both the upper and lower Dirac cones that constitutes strong evidence of the orbital-dependent spin texture in Bi2Se3. The different spin texture detected in variable polarization geometry is the manifestation of the spin-orbital texture in the initial state combined with the photoemission matrix element effects. Our observations provide a new orbital degree of freedom and a new way of light manipulation in controlling the spin structure of the topological insulators that are important for their future applications in spin-related technologies.
@article{arxiv.1303.0698,
title = {Orbital-Selective Spin Texture and its Manipulation in a Topological Insulator},
author = {Zhuojin Xie and Shaolong He and Chaoyu Chen and Ya Feng and Hemian Yi and Aiji Liang and Lin Zhao and Daixiang Mou and Junfeng He and Yingying Peng and Xu Liu and Yan Liu and Guodong Liu and Xiaoli Dong and Jun Zhang and Xiaoyang Wang and Qinjun Peng and Zhimin Wang and Shenjin Zhang and Feng Yang and Chuangtian Chen and Zuyan Xu and X. J. Zhou},
journal= {arXiv preprint arXiv:1303.0698},
year = {2015}
}