MgS晶体结构性质的密度泛函研究

Density functional theory investigation on structural properties of MgS crystal

采用基于密度泛函理论(DFT)基础上的第一性原理赝势平面波方法对MgS晶体四种构型(B1,B2,B3,B4)的体相性质进行了系统研究.计算结果表明,B1构型的晶体是间接带隙型半导体,而B2,B3和B4构型的晶体则是直接带隙型材料,其中B2构型的带隙宽度最窄,其值为0.42eV.在压力不超过200.3GPa时,B1构型的MgS晶胞是最稳定的,当压力大于该值时,会发生B1构型到B2构型的转化.

We have systematically studied the structural and electronic properties of MgS crystal by means of accurate first principle calculations. Our results show that this crystal has indirect band gap in the B1 structure and direct band gap in the B2, B3 and the B4 structures. Energy band width of the B2 structure is the smallest. When the pressure is below 200.3GPa, the B1 structure of MgS crystal is most stable. Above 200.3GPa this compound would undergo a structural phase transition from the relatively loose NaCl structure to the more dense CsC1 atomic arrangement.