Atomistic simulations studies of the bulk cobalt pentlandite (Co$_9$S$_8)$: Validation of the potential model

We investigate various forms of the cobalt pentlandite, Co$_{9}$S$_{8}$, at different temperatures, using classical atomistic simulation methods with the support of electronic structure calculations. The first interatomic potentials of Co$_{9}$S$_{8}$ based on the Born model, were derived with input data such as structure and elastic properties from experiments and electronic structure calculations respectively. The interatomic potentials were validated by running energy minimization and molecular dynamics calculations. The structure, elastic properties and phonon spectra corresponded well with those determined by electronic structure methods. The calculations further reproduced the complex high temperature transformation to high form pentlandite and the melting of Co$_{9}$S$_{8}$; as deduced from the crystal structure and radial distribution functions. The interatomic potentials can be used for studies of surfaces and nanostructures.