Computational investigation of sulfosalts*

Sulfosalts form a vast mineral group which may be imagined as chemically analogous to oxides, with O replaced by S. However, the metal cations in sulfosalts generally have tetrahedral S coordination, and the chemical variety is much greater than in oxides, owing to the several possible oxidation states of sulfur. Structurally they range from the very simple to the very complex, and also span the whole range of anisotropies, from chainlike to fully 3D. They are less ionic than oxides, thus they display surprising crystallochemical flexibility and superior tunability of the valence of the transition metal ions. This results in a large variety of interesting electronic, magnetic and mechanical properties. Here we present an initial study of a particular class of sulfosalts, based on murunskite. The electronic structure is discussed with respect to possible signatures of thermoelectricity and superconductivity.