The incorporation of Cadium, Manganese and Ferrous Iron in Sphalerite: Insights from Computer Simulations

Abstract

Techniques of atomistic simulation have been used to study the incorporation of the M2+ impurities iron, manganese and cadmium into sphalerite. The calculations show that bulk impurity ions are most easily incorporated by direct substitution at the Zn site, and that the substitution energies exhibit a linear relationship with ionic radii. Furthermore, there appears to be no driving force for the creation of clusters, or any barrier to their formation. However, the formation of iron pairs leads to deviations from Vegard's Law. Simulations of pure ZnS surfaces have identified a new reconstruction for the zinc-terminated (111), which has the lowest energy of all {111}-type surfaces. Furthermore, impurities can exchange with zinc more easily on (111) than on any of the other surfaces studied. The results of the simulations show that crystal morphology and surface structure will exert an influence on uptake of impurities, with the effect being most noticeable for cadmium and least important for iro