Vacancy Induced Structural and Electronic Properties of Two Dimensional Stanene: A First Principles Investigation

Although graphene, the first two dimensional (2D) material has brought a revolutionary change in the field of nanotechnology with its exotic electronic, optical and mechanical properties, its zero band gap resists its use in logic circuit application. Recently, graphene like hexagonal crystal structured 2D stanene, a sheet of tin (Sn) attracts a great attention in the present nanotechnology research, owing to its large spin orbital coupling (SOC) induced band gap and intriguing quantum spin hall (QSH) effect. Nevertheless, during the synthesis of stanene monolayers, defects are inevitably present which affect the structural as well as electronic properties of the material. Hence, within this work, we applied first principles calculation to systematically investigate the effect of vacancy type defects such as single vacancy and double vacancy on the structural and electronic properties of stanene monolayer. The pristine stanene sheet shows zero band gap feature; however, when SOC is considered, a band gap of about 76.6 meV is found which is very promising for the application as topological insulator. Moreover, when single and double vacancies are introduced, stanene shows a metallic as well as n-type characteristic. Furthermore, double vacancy induces more semiconducting characteristics than single vacancy. Our results suggest a theoretical basis for the potential application of this material with the natural vacancy defects in the nanoelectronic and optoelectronic devices.