高温高压下ZnO的相变及热力学性质研究(英文)

First-principles calculation for phase transitions and thermodynamic properties of ZnO under high temperature and high pressure

本文通过平面波赝势密度泛函理论研究了ZnO岩盐(B1)结构、CsCl(B2)结构、闪锌矿(B3)结构和纤锌矿(B4)结构的相变和热力学性质.通过计算得到了晶格常数、体弹模量及体弹模量对压强的一阶导数,与实验值和其他计算结果都符合地较好.根据等焓原理,发现从B4和B3结构到B1结构的相变压强分别约为8.9GPa和7.8GPa.通过准德拜模型,成功得到B4结构的热力学性质,包括不同压强和温度下的状态方程、热膨胀系数和热容.

In the work we have investigated the phase transitions and thermodynamic properties of wurtz- ite sturcure （B4）, zinc blende structure （B3）, rocksolt structure （B1） and CsC1 structure （B2） of ZnO by the plane-wave pseudopotential density functional theory method. The obtained lattice constant a, the isothermal bulk modulus B0 and its pressure derivative B＇0 are consistent with the experimental and other calculated results. According to the condition of equal enthalpies, we find that the phase transi tions from the B4 and B3 structures to the B1 structure occur at about the pressure of 8.9 GPa and 7.8 GPa, respectively. Through the quasi-harmonic Debye mode, the thermodynamic properties of B4 struc- ture, including the equation of state, thermal expansion, heat capacities at different temperatures and pressures, are successfully investigated.