First-principles study of the anisotropic thermal expansion of wurtzite ZnS

In this letter, a first-principles study of the anisotropic thermal expansion of wurtzite ZnS in the framework of the density-functional theory and the density-functional perturbation theory is reported. The compound in zinc blende structure is also studied for comparison. The curves of the linear and volume thermal expansion coefficients to temperature are presented. The volume thermal expansion coefficient of zinc blende ZnS changes from smaller to larger than that of wurtzite ZnS as temperature increases. The theoretical cross point is at 867 K. The recent experimental observation of phase controlled synthesis of ZnS nanomaterials is explained from the viewpoint of Gibbs free energy. (c) 2006 American Institute of Physics.