State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China and Collaborative Innovation Center of Quantum Matter, Beijing 100084, China and Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China and Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
Phys Rev Lett. 2014 May 9;112(18):186801. doi: 10.1103/PhysRevLett.112.186801. Epub 2014 May 5.
The surface of a topological crystalline insulator (TCI) carries an even number of Dirac cones protected by crystalline symmetry. We epitaxially grew high-quality Pb(1-x)Sn(x)Te(111) films and investigated the TCI phase by in situ angle-resolved photoemission spectroscopy. Pb(1-x)Sn(x)Te(111) films undergo a topological phase transition from a trivial insulator to TCI via increasing the Sn/Pb ratio, accompanied by a crossover from n-type to p-type doping. In addition, a hybridization gap is opened in the surface states when the thickness of the film is reduced to the two-dimensional limit. The work demonstrates an approach to manipulating the topological properties of TCI, which is of importance for future fundamental research and applications based on TCI.
拓扑晶体绝缘体（TCI）的表面承载着由晶体对称性保护的偶数个狄拉克锥。我们外延生长了高质量的 Pb(1-x)Sn(x)Te(111) 薄膜，并通过原位角分辨光发射谱研究了 TCI 相。随着 Sn/Pb 比的增加，Pb(1-x)Sn(x)Te(111)薄膜经历了从平凡绝缘体到 TCI 的拓扑相变，同时掺杂类型也从 n 型转变为 p 型。此外，当薄膜厚度减小到二维极限时，表面态中会出现杂化能隙。这项工作展示了一种操控 TCI 拓扑性质的方法，这对于基于 TCI 的未来基础研究和应用具有重要意义。
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