The lattice thermal $\mathrm{conductivity}({\kappa }_{\mathrm{L}}$) of most single crystals usually follows $T^{-1}$ temperature dependent relation at high temperature region. Here, we investigate the microscopic mechanism of the significant deviation of ${\kappa }_{\mathrm{L}}\sim T^{-1}$ rule in Cu-based chalcopyrite compounds $\mathrm{CuIn}{X}_2$($X$=Se, Te) by performing first-principles calculations and solving Peierls-Boltzmann transport equation with phonon anharmonic renormalization. The temperature sensitive second-order force constants lead to the dramatically softened optical phonon bands, which contributes to the enlarged phonon scattering phase space and consequent enhanced scattering rate. The strong temperature dependent thermal conductivity in $\mathrm{CuIn}{X}_2$($X$=Se, Te) can be well reproduced when calculating thermal conductivity with renormalization force constants. The motion of Cu contributes the most to the large anharmonicity at high temperature, which makes the anharmonic renormalization non-negligible for estimating accurate lattice dynamic and thermal conductivity. Our work will deepen the understanding of thermal transport property of Cu-based chalcopyrite, which is helpful for designing better thermoelectric or photovoltaic devices.

中文翻译：

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CuInX2(X=Se, Te)中非谐性引起的强温度相关热导率

晶格热$\mathrm{电导率}({\kappa }_{\mathrm{大号}}$) 大多数单晶通常如下${吨}^{-1}$高温区的温度依赖关系。在这里，我们研究了显着偏差的微观机制${\kappa }_{\mathrm{大号}}～{吨}^{-1}$铜基黄铜矿化合物的规律$铜X_2$($X$=Se, Te) 通过执行第一性原理计算和求解具有声子非谐重整化的 Peierls-Boltzmann 输运方程。温度敏感的二阶力常数导致光学声子带显着软化，这有助于扩大声子散射相空间并随之提高散射率。与温度相关的强热导率$铜X_2$($X$=Se，Te) 在用重整化力常数计算热导率时可以很好地再现。Cu的运动对高温下的大非谐性贡献最大，这使得非谐重整化对于估计准确的晶格动力学和热导率是不可忽略的。我们的工作将加深对铜基黄铜矿热传输特性的理解，有助于设计更好的热电或光伏器件。