摘要:
基于第一性原理平面波赝势(PWP)和广义梯度近似(GGA)方法,对闪锌矿结构(ZB)和岩盐结构(RS)的ZnSe在0-20 Gpa高压下的几何结构、态密度、能带结构进行了计算研究,分析了闪锌矿结构ZnSe和岩盐结构ZnSe的几何结构.在此基础上,研究了ZnSe的结构相变、弹性常数、成键情况以及相变压强下电子结构的变化机理.结果发现:通过焓相等原理得到的ZB相到RS相的相变压强为15.3 Gpa,而由弹性常数判据得到的相变压强为11.52GPa,但在9.5 Gpa左右并没有发现简单立方相的出现;在结构相变过程中,sp~3轨道杂化现象并未消除,Zn原子的48电子在RS相ZnSe的导电性中起主要贡献.
Abstract:
Geometric structures, density of states and band structures of zinc blend structure and rock salt structure of ZnSe at different pressures (from 0 to 20 Gpa) have been calculated by means of plane wave pseudo-potential method with generalized gradient approximation.The structural phase transitions, elastic constants, bonding and electronic structures of ZnSe under pressure have been discussed.From the principle of enthalpy for the zincblende and rocksalt ZnSe, the pressure at the phase transition is 15.3 Gpa, which is higher than the result of 11.52 Gpa deduced from the elastic constants of the phase transition criterion.The change of phase to simple cubic has not been found at the pressure of 9.5GPa; and the sp~3 hybrid orbital has not been eliminated during the structure phase transition, while the 4s electronic state of Zn atom has a major contribution to the conductivity in rocksalt phase.
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