各向异性压力对ZnS晶体结构和电子性能的影响研究

Effects of Anisotropic Pressure on Crystal Structure and Electronic Properties of ZnS

基于电子平面波密度泛函理论的方法研究分析了闪锌矿结构ZnS在未受压力和沿a,b和c轴方向上受0.5GPa小压力条件下的晶体结构和电子性质。结果表明闪锌矿ZnS在0.5 GPa的不同方向小压力作用下,晶胞参数均发生增大,表现出较为明显的压力膨胀效应。压力对ZnS晶体结构的影响是各向异性的,其对ZnS晶体c轴方向的影响最大,压力作用下Zn-S键长也均增大。ZnS体系在0.5 GPa压力下稳定性增强,其在a轴受压力作用下能量最低。在a轴,b轴和c轴方向施加相同压力之后,ZnS的带隙宽度由2.059 eV分别减小到1.683 eV,1.681 eV和1.681 eV,但是其带隙类型未发生变化。ZnS材料体系中的p态电子对费米能级附近的贡献程度最高,而s态和d态电子对费米能级处的贡献程度均较低。

The crystal structure and the electronic properties of the blende type ZnS without compressional pressure as well as under 0. 5 GPa compressional stress along a,b and c axis directions were investigated by plane wave density funtional theory method. The results show that the lattice parameters can be increased slightly at 0. 5 GPa low compressional pressure,the obviously negative expansion effect can be found. The anisotropic pressure effect on the crystal structure can also be found and this effect on the c axis direction is strongest,the bond length of Zn-S has increased too. The stability of ZnS can be enhanced at 0. 5 GPa compressional pressure,the total energy is lowest at compressing pressure along aaxis. The band gap has been decreased from 2. 059 eV to 1. 683 eV,1. 681 eV and 1. 681 eV respectively at compressing pressure along a,b and c axis. The band gap remains direct. The p state electrons contribute to density of states very much and the s as well as the d state electrons contributes less to density of states near Fermi level.