Defects and Impurities Induced Structural and Electronic Changes in Pyrite CoS₂: First Principles Studies

Pyrite-type transition-metal (TM) dichalcogenides are attracting considerable attention in wide application fields, in particular cobalt pyrite (CoS₂) which has been widely used in many electrochemical areas such as batteries, supercapacitors, catalysts and so on. In this work, systematic first-principles calculations were performed to investigate the effects of various neutral defects and ion dopings on the structural, energetic, electronic and magnetic properties of bulk cobalt pyrite (CoS₂). It was found that the single-S vacancy has more effect on electronic properties of CoS₂ than Co vacancies due to the destroy of the O_h symmetry. O_S centers are electronic dopants and do not induce any impurity state. The Group IV and V impurities (C, Si, N, P, and As) have effects on both majority- and minority-spin channels, resulting in the spin moment change of ~1.0 µ_B per impurity atom. But the Group VII elements (F, Cl, and Br) only influences the minority-spin. Our extensive calculations provide instructive information for the design and optimization of CoS₂-related energy materials.