C轴压力下ZnO晶体结构及电子性质的第一性原理研究

Structure and electronic properties of ZnO crystal under C-axis pressure by first principles study

本文采用基于密度泛函理论(DFT)的第一性原理方法对ZnO晶体在c轴取向压力作用下的晶体结构、电子结构的变化进行了研究.结果表明,当压力在0～6 GPa区间时,晶格参数呈线性变化,带隙随压力增大而增大,显示弹性应变特征;当压力从6 GPa增大到10 GPa的过程中,晶体结构有了较大变化,出现了介于常压下纤锌矿结构和等静压高压下NaCl结构之间的类石墨结构(Graphitelike structure).伴随着这一结构相变,ZnO的晶格参数,能隙和态密度等电子结构出现了较大跃变.

In this article, the first-principles method based on the density functional theory （DFT） was employed to investigate the structural and electronic properties of ZnO under unixial pressure along c-axis. It was found that the properties of ZnO crystal are very sensitive to the applied pressures. When pressure increases from 0 to 6 GPa, both energy band gap and lattice parameters show nearly linearly changes against pressure. At higher pressures （6 GPa to 10 GPa）, a graphitelike phase with a structure between Wurtzite and high pressure NaCl phase occurs. Accordingly, significant changes in crystal structures and energy band structures were also observed in association with this phase transition.