利用基于密度泛函的第一性原理,计算ⅥA族元素Se和Te在常压下的能带结构、电子态密度、弹性系数和德拜温度.能带结构和电子态密度的计算结果表明:Se为间接带隙半导体,Se费米面附近的导带和价带主要来自外层4p4电子的贡献,4s2电子对费米面附近的导带和价带贡献较少;Te为直接带隙半导体,Te费米面附近的导带和价带主要来自外层5p4电子的贡献,5s2电子对费米面附近的导带和价带贡献较少.弹性系数计算结果表明:常压下具有六角结构的Se和Te的力学性质稳定;其德拜温度分别为263 K和315 K.
An investigation of the electronic,elastic and thermodynamic properties of VC under high pressure has been conducted using first-principles calculations based on density functional theory (DFT) with the plane-wave basis set,as implemented in the CASTEP code. At elevated pressures,VC is predicted to undergo a structural transition from a relatively open NaCl-type structure to a more dense CsCl-type one. The predicted transition pressure is 520 GPa. The elastic constant,Debye temperature and heat capacity each as a function of pressure and/or temperature of VC are presented for the first time.
