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arXiv 1209.6350cond-mat.mtrl-scicond-mat.mes-hallphysics.comp-ph
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砷化镓热导率和光学声子弛豫时间的第一性原理计算

Gallium Arsenide Thermal Conductivity and Optical Phonon Relaxation Times from First-Principles Calculations

Tengfei Luo, Jivtesh Garg, Junichiro Shiomi, Keivan Esfarjani, Gang Chen

摘要:

本文采用第一性原理晶格动力学方法计算了GaAs晶体的热导率。谐波和立方力常数通过将它们拟合到来自密度泛函理论计算的力-位移数据而获得。利用简谐力常数构造的动力学矩阵计算声子色散,利用费米黄金定则计算声子弛豫时间。计算的GaAs热导率与实验数据吻合良好。得到了热导累积随声子平均自由程和波长的变化关系。我们的研究结果预测在纳米尺度下GaAs的热导率有显著的尺寸效应。研究了光学声子的弛豫时间及其在不同散射通道中的贡献。这些信息将有助于理解热声子效应的GaAs基器件。

英文摘要:

In this paper, thermal conductivity of crystalline GaAs is calculated using first-principles lattice dynamics. The harmonic and cubic force constants are obtained by fitting them to the force-displacement data from density functional theory calculations. Phonon dispersion is calculated from dynamical matrix constructed using the harmonic force constants and phonon relaxation times are calculated using Fermi Golden rule. The calculated GaAs thermal conductivity agrees well with experimental data. Thermal conductivity accumulations as a function of phonon mean free path and as a function of wavelength are obtained. Our results predict significant size effect on the GaAs thermal conductivity in the nanoscale. Relaxation times of optical phonons and their contributions from different scattering channels are also studied. Such information will help understanding hot phonon effects in GaAs-based devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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