Quasi-periodic scattering of topological edge states induced by the vacancies in chloridized gallium bismuthide nanoribbons.

The chloridized gallium bismuthide was predicted to be a two-dimensional topological insulator with large topological band gap. It may be beneficial for achieving the quantum spin Hall effect and its related applications at high temperatures. To better understand the quantum transport in topological nanoribbons, we investigated the effect of vacancy on the quantum transport of topological edge states in the armchair chloridized gallium bismuthide nanoribbons by combining density functional theory and nonequilibrium Green's function. The results suggest the vacancies at center are more likely to cause the scattering of topological edge states. The average scattering is insensitive to the enlargement of vacancy along the transport direction. More interestingly, the obvious scattering of topological edge states can only be found at some special energies, and these special energies are distributed quasi-periodically. The quasi-periodic scattering may be used as a kind of fingerprint of vacancies. Our studies may be helpful for the application of topological nanoribbons.