Structural and electronic properties of CaS Crystal: A density functional theory investigation

We have systematically studied the structural and electronic properties of CaS crystal by means of first-principle calculations. Our results show that this material has indirect-band-gap in the B2 structure and direct band gap in the B1, B3 and B4 structures for CaS. When the pressure is below 36.5 GPa, the B1 structure is the most stable. Above 36.5 GPa this compound will undergo a structural phase transition from the relatively open NaCl structure into the more dense CsCl atomic arrangement.