高温高压下闪锌矿相GaN结构和热力学特性的分子动力学研究

Molecular dynamics study on the structural and thermodynamic properties of the zinc-blende phase of GaN at high pressures and high temperatures

利用分子动力学方法和Buckingham经验势模型对重要半导体材料GaN立方闪锌矿相的晶格常数、相变压力(从闪锌矿到岩盐结构)、热膨胀、等温体模量、定压热容等结构和热力学特性在300—3000K的温度范围和0—65GPa的压力范围内进行了研究.研究表明,闪锌矿相GaN常态下的结构和热力学参数的模拟结果与实验数据及其他理论结果相符.同时在所选作用势模型可靠性检验的基础上,对等温体模量、定压热容诸非谐性参量在高温高压下的热力学行为进行了预测.所得结果在材料科学等领域的研究中具有一定的应用背景和参考价值.

The structural and thermodynamic properties of zinc-blende phase of GaN have been investigated systematically using the molecular dynamics method with Buckingham potential model. These properties including lattice constant, phase transition pressure （from the zinc-blende to the rock-salt structure）, thermal expansion, isothermal bulk modulus, and heat capacity at constant pressure were calculated in a wide range of temperatures （300-3000 K） and pressures （0-65 GPa）. The structural and thermodynamic parameters obtained under normal state are found to be in good agreement with the existing experimental and theoretical results. Meanwhile, some thermodynamic parameters such as isothermal bulk modulus and heat capacity at constant pressure have been predicted at elevated temperatures and high pressures based on the reliable potential model. The simulated results are of fundamental importance in material science.