1. Two-Dimensional Topological Crystalline Insulator and Topological Phase Transition in TlSe and TlS Monolayers
- Author
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Patrick M. Buhl, Stefan Blügel, Gustav Bihlmayer, Chengwang Niu, Yuriy Mokrousov, and Daniel Wortmann
- Subjects
Chern class ,Materials science ,Condensed matter physics ,Mechanical Engineering ,Bioengineering ,Insulator (electricity) ,General Chemistry ,Condensed Matter Physics ,Topology ,Symmetry protected topological order ,Condensed Matter::Materials Science ,Topological insulator ,Monolayer ,Topological order ,General Materials Science ,Edge states ,Quantum well - Abstract
The properties that distinguish topological crystalline insulator (TCI) and topological insulator (TI) rely on crystalline symmetry and time-reversal symmetry, respectively, which encodes different bulk and surface/edge properties. Here, we predict theoretically that electron-doped TlM (M = S and Se) (110) monolayers realize a family of two-dimensional (2D) TCIs characterized by mirror Chern number CM = -2. Remarkably, under uniaxial strain (≈ 1%), a topological phase transition between 2D TCI and 2D TI is revealed with the calculated spin Chern number CS = -1 for the 2D TI. Using spin-resolved edge states analysis, we show different edge-state behaviors, especially at the time reversal invariant points. Finally, a TlBiSe2/NaCl quantum well is proposed to realize an undoped 2D TCI with inverted gap as large as 0.37 eV, indicating the high possibility for room-temperature observation.
- Published
- 2015