Experimental Demonstration of Topological Surface States Protected by Time-Reversal Symmetry

作者：Tong Zhang, Peng Cheng, Xi Chen, Jinfeng Jia, Xu-Cun Ma, Ke He, Lili Wang, Haijun Zhang, Xi Dai, Zhong Fang, X. C. Xie, Qi‐Kun Xue · 发表于：Physical Review Letters · 年份：2009 · DOI：10.1103/physrevlett.103.266803 · 被引用次数：750 · 研究领域：Topological Materials and Phenomena、Photonic Crystals and Applications、Random lasers and scattering media

We report direct imaging of standing waves of the nontrivial surface states of topological insulator Bi2Te3 using a scanning tunneling microscope. The interference fringes are caused by the scattering of the topological states off Ag impurities and step edges on the Bi2Te3(111) surface. By studying the voltage-dependent standing wave patterns, we determine the energy dispersion E(k), which confirms the Dirac cone structure of the topological states. We further show that, very different from the conventional surface states, backscattering of the topological states by nonmagnetic impurities is completely suppressed. The absence of backscattering is a spectacular manifestation of the time-reversal symmetry, which offers a direct proof of the topological nature of the surface states.