Vacancy induced magnetism and electronic structure modification in monolayer hexagonal boron arsenide: A first-principles study

The effect of 0D vacancy defects on the structural, electronic, magnetic, and optical properties of dynamically stable hexagonal boron arsenide monolayer was comprehensively studied using first-principles calculations. Five configurations of 0D vacancy defects — single boron vacancy, double boron vacancy, single arsenic vacancy, double arsenic vacancy, and single boron-single arsenic vacancy, were considered. Our density functional theory calculations indicated that arsenic vacancy induced magnetism (1.0 μB) in the boron atoms around the vacancy site, whereas induced magnetism was absent for other vacancy defects. The magnitude of the induced magnetic moment for arsenic vacancy decreased with the increasing concentration of vacancy. Semiconductor to metal transition was noticed due to the introduction of single boron vacancy, double boron vacancy and double arsenic vacancy. Single boron–arsenic vacancy decreased the pristine band gap though finite band gap remained. Instigating 0D vacancy modified the optical absorption spectra of the monolayer. Work function calculations revealed that the work function increased after vacancy defect was introduced. This work will be beneficial to ascertain the multifunctionality of the defective boron arsenide monolayer as 2D nanomaterials for optoelectronic and spintronic applications.