GaAs相变和热力学性质的密度泛函理论研究

利用平面波赝势密度泛函方法,对GaAs从闪锌矿结构到CsCl 结构的相变进行了理论研究.通过Birch-Murnaghan状态方程拟合闪锌矿结构GaAs的能量和体积,得到了GaAs的热力学性质.我们发现对 GaAs来说,闪锌矿结构通常比CsCl结构稳定,由闪锌矿结构到CsCl结构的相变压力在37.019 GPa左右.计算所得到的晶格常数、体弹模量及体弹模量对压强的一阶导数与实验值以及其他作者的计算值相符合.

Transition phase and thermodynamic properties of GaAs

The transition phase of GaAs from ZB structure to CsCl structure is investigated by a plane-wave pseudopotential density functional theory method, and the thermodynamic properties of the ZB structure are obtained by fitting the total energy versus volume to the Birch-Murnaghan equation of state (EOS). It is found that the ZB structure of GaAs is more stable than the CsCl structure under ambient condition, and the transition phase from the ZB structure to CsCl structure occurs at the pressure of 37. 019 GPa. The obtained lattice constant, bulk modulus and pressure derivative of bulk modulus are consistent with the experimental data and those calculated by others.