First Principles Calculations of Getchellite AsSbS3 in Bulk and Monolayer Structures

Herein, periodic density-functional theory calculations for both bulk and monolayer structures of the getchellite (AsSbS3) compound are reported. The experimental crystal structure is modelled with partial occupations by using a supercell, the resulting structure being found to be dynamically stable. The Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) calculations show that AsSbS3 is a semiconductor with an indirect bandgap of 1.62 and 2.30 eV for the bulk structure, and of 1.90 and 2.64 eV for the monolayer. Also, it is identified that the conduction band minimum is mostly due to the contribution of p-As, p-Sb, and s-S orbitals, while the valence band maximum corresponds mainly to the contribution of p-S orbitals.