Quantum spin hall charge pumping characterized by symmetry in 2D topological Sb2S3 insulator

Abstract

The quantum spin hall (QSH) insulator in a hexagonal lattice motivates the future searching for novel two-dimensional (2D) materials due to the potential applications caused by the dissipationless helical edges located in the band gap on spintronic devices, in which the symmetry of crystals has a significant effect on topological properties. Here, we investigate the topological property of the Sb2S3 monolayer by means of the group theory and symmetries based on first principle calculations. Our results demonstrate that the Sb2S3 monolayer is a Z2 insulator with a huge bulk band gap of 252 meV in the presence of SOC effect. The characterization of topological non-trivial band gap is the irreducible representation of the conduction band and valence band undergoes a reversal when crossing the path along the band gap under the operation of crystal point groups, resulting in the band inversion. This result is convinced by the evolution of the wave-functions. Our finding deepens the insight into the quantum hall effects and provides some theoretical ideas for a deeper knowledge on topological non-trivial band.