固体氩的晶格热导率的非简谐晶格动力学计算

用一种非简谐晶格动力学方法, 使用相互作用势作为惟一的输入参数, 准确地计算了固体氩的各个声子的频率和弛豫时间. 并将这些结果进一步和玻尔兹曼输运方程相结合, 预测了固体氩从10 K 到80 K 区间的热导率, 并得到了与实验值非常符合的结果. 分析了运用非简谐晶格动力学方法进行数值计算过程中的各个相关的计算参数, 包括布里渊区中倒格子矢量的选取, δ 函数的展宽的选择等对热导率和声子弛豫时间预测结果的影响. 通过对各个声子模式对热导率贡献的分析, 发现随着温度升高, 高频声子对于热导率的贡献率也逐渐变大, 结果和理论预测完全一致. 关键词： 热导率 固体氩 非简谐晶格动力学 声子

Prediction of lattice thermal conductivity of solid argon from anharmonic lattice dynamics method

Anharmonic lattice dynamics method is employed to investigate the phonon frequency and relaxation time without any fitting parameters. The phonon relaxation time is used in Boltzmann transport equation to predict the lattice thermal conductivity of solid argon between 10 K and 80 K, and the results agree very well with experimental data. The effects of calculation parameters on the prediction accuracy are also analyzed, including mesh size of the reciprocal lattice points, and the broadening factor of delta function. The contribution of each individual phonon mode to the thermal conductivity is investigated. It is found that higher frequency phonons contribute more to the thermal conductivity at higher temperature, which is consistent with previous theoretical results.
Keywords： thermal conductivity solid argon anharmonic lattice dynamics phonon