Lattice thermal conductivities of two SiO2 polymorphs by first-principles calculations and the phonon Boltzmann transport equation
Lattice thermal conductivities of two SiO2 polymorphs by first-principles calculations and the phonon Boltzmann transport equation
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DOI：
10.1103/physrevb.97.224306
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发表时间：
2018-06-15
影响因子：
3.7
通讯作者：
Tanaka, Isao
中科院分区：
文献类型：
--
作者：
Mizokami, Keiyu;Togo, Atsushi;Tanaka, Isao
利用第一性原理非谐波声子计算和线性化声子玻尔兹曼输运方程，研究了石英（低）和方石英（低）两种SiO2多晶态材料的晶格热导率。虽然石英和方英石具有相似的声子密度态，但声子群速度和寿命的声子频率依赖关系不同，这导致晶格热导率的各向异性差异很大。对于石英和方英石，确定晶格热导率的声子寿命分布可以很好地描述为由声子占据数加权的三个声子散射的能量和动量守恒，以及代表声子-声子相互作用强度的一个参数。
Lattice thermal conductivities of two SiO2 polymorphs, i.e., alpha quartz (low) and alpha cristobalite (low), were studied using first-principles anharmonic phonon calculation and linearized phonon Boltzmann transport equation. Although alpha quartz and alpha cristobalite have similar phonon densities of states, phonon frequency dependencies of phonon group velocities and lifetimes are dissimilar, which results in largely different anisotropies of the lattice thermal conductivities. For alpha quartz and alpha cristobalite, distributions of the phonon lifetimes effective to determine the lattice thermal conductivities are well described by energy and momentum conservations of three phonon scatterings weighted by phonon occupation numbers and one parameter that represents the phonon-phonon interaction strengths.