Modification of electronic structure, magnetic structure, and topological phase of bismuthene by point defects

Abstract

This paper reveals how electronic, magnetic structure and topological phase of 2D, single-layer structures of bismuth are modified by point defects. We first showed that free standing, single-layer, hexagonal structure of bismuth, named as h-bismuthene exhibits non-trivial band topology. We then investigated interactions between single foreign adatoms and bismuthene structures, which comprise stability, bonding, electronic and magnetic structures. Localized states in diverse location of the band gap and resonant states in band continua of bismuthene are induced upon the adsorption of different adatoms, which modify electronic and magnetic properties. Specific adatoms result in reconstruction around the adsorption site. Single and divacancies can form readily in bismuthene structures and remain stable at high temperatures. Through rebondings Stone-Whales type defects are constructed by divacancies, which transform into a large hole at high temperature. Like adsorbed adatoms, vacancies induce also localized gap states, which can be eliminated through rebondings in divacancies. We also showed that not only optical and magnetic properties, but also topological features of pristine h-bismuthene can be modified by point defects. Modification of topological features depends on the energies of localized states and also on the strength of coupling between point defects.