Realization of versatile electronic, magnetic properties and new topological phases in hydrogenated bismuthene

Abstract

Recently, bismuthene grown on SiC substrate has been confirmed to serve as a candidate for high-temperature quantum spin Hall (QSH) material, which opens a new direction to engineer actual QSH effect. In order to explore possible routes to modify the electronic and magnetic properties of the existed bismuthene, we construct the hydrogenated bismuthene model and perform systematical calculations of 22 kinds of adatoms. H and O hybridize strongly with the hydrogenated bismuthene sheet, and B, C, Al, Si, K, and Ge implement local magnetic moment, resulting in the intrinsic QSH state perturbed. Particularly, new QSH phase is found in group -V and -VI adatoms depositions, which is original from the strong p –p hybridization of Bi and adatoms, and entirely different from the intrinsic QSH state. The largest fundamental band gap is predicted to be about 140 meV. We find that a promising way to achieve Rashba effect in 2D topological insulator is to make use of group-VI atoms depositing on the hydrogenated bismuthene sheet. Moreover, 4d and 5d transition-metal atoms are expected to produce quantum anomalous Hall (QAH) effect due to weak p –d hybridization and rare localized magnetism. For transition-metal atoms, GGA + U correction is further used to check the electronic and magnetic properties. Our results show various electronic and magnetic properties of the hydrogenated bismuthene and present some possible routes to realize new QSH and QAH states, which are helpful for widening the applications of the existed bismuthene.