Jia Shuang, Xu Su-Yang, Hasan M Zahid
International Center for Quantum Materials, School of Physics, Peking University and at the Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, New Jersey 08544, USA.
Nat Mater. 2016 Oct 25;15(11):1140-1144. doi: 10.1038/nmat4787.