title: Two-Dimensional Topological Crystalline Insulator and Topological Phase Transition in TlSe and TlS Monolayers.
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.
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany.
authors.forename: Chengwang
authors.initials: C
authors.lastname: Niu
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Buhl
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany.
authors.forename: Gustav
authors.initials: G
authors.lastname: Bihlmayer
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wortmann
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Blügel
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany.
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Mokrousov
keywords: 2D topological crystalline insulator; 2D topological insulator; edge states; mirror Chern number; spin Chern number; topological phase transition