On the effect of non-stoichiometry on electronic and magnetic properties of BiOCuS layered oxysulfide: A preliminary consideration based on ab initio band structure simulations

This paper presents the theoretical consideration of electronic structure and magnetic properties of non-stoichiometric BiOCu1-xS layered oxysulfide being the related phase for BiOCu0.9S superconductor with T-c = 5.8 K. Based on ab initio band structure computations the effect of hole doping (due to copper vacancies) on its electronic and magnetic state has been traced in comparison with the pristine compound. The copper non-stoichiometry results both in electrical conductivity of imperfect BiOCuS and in turning it into magnetic state, which was characterized as weak band ferromagnetism. Herewith, both transport and spin electronic density appear to be concentrated predominantly within Cu-S] layers in crystal, while [Bi-O] structural blocks are rather insensitive to hole doping, so the conditional layered model of active slabs interchanged with passive gaskets for BiOCu1-xS has been suggested. The consistence of the obtained results with available experimental data also has been discussed and the possible reasons of their disagreement have been proposed. (C) 2018 Elsevier B.V. All rights reserved.