Electronic and structural properties of bulk arsenopyrite and its cleavage surfaces - a DFT study

Arsenopyrite is the most abundant arsenic containing mineral on Earth and it is normally associated with many other minerals of economic importance. Therefore, it is involved in the environmental impacts of mining activities. The bonding nature of arsenopyrite and its preferential cleavage surface are still controversial. In the present work we have investigated the structural and electronic properties of arsenopyrite and its cleavage surface formation using a density functional/plane waves method. The quantum theory of atoms in molecules (QTAIM) and electron localization function (ELF) were applied for investigating the nature of the bonding in arsenopyrite. No evidence was found for Fe-Fe bonding in the bulk structure. The As-S bond has large covalent character and it is unexpected to be broken in the surface formation. The cleavage and surface energies have been calculated indicating that the (001) surface is the most favored.