Thermal conductivity of diamond under extreme pressure: A first-principles study
Thermal conductivity of diamond under extreme pressure: A first-principles study
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DOI：
10.1103/physrevb.86.115203
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发表时间：
2012-09-06
影响因子：
3.7
通讯作者：
Ward, A.
中科院分区：
文献类型：
--
作者：
Broido, D. A.;Lindsay, L.;Ward, A.
使用基于密度泛函微扰理论和声子玻尔兹曼方程的精确数值解的第一性原理方法，我们表明，应用高压缩流体静压显着增加金刚石的热导率。我们将这种增强与整体增加的频率尺度与压力联系起来，这使得声速更高，并降低了声子-声子散射率。特别重要的是经常被忽视的事实，即热携带的声学声子通过晶格非谐性耦合到更高频率的光学模式。光学模式频率随压力的增加削弱了这种耦合，并有助于将金刚石热导率驱动到比环境压力和温度下的任何材料大得多的值。
Using a first-principles approach based on density functional perturbation theory and an exact numerical solution to the phonon Boltzmann equation, we show that application of high compressive hydrostatic pressure dramatically increases the thermal conductivity of diamond. We connect this enhancement to the overall increased frequency scale with pressure, which makes acoustic velocities higher and reduces phonon-phonon scattering rates. Of particular importance is the often-neglected fact that heat-carrying acoustic phonons are coupled through lattice anharmonicity to higher frequency optic modes. An increase in optic mode frequencies with pressure weakens this coupling and contributes to driving the diamond thermal conductivities to far larger values than in any material at ambient pressure and temperature.