Metavalent bonding induced abnormal phonon transport in diamondlike structures: Beyond conventional theory
Metavalent bonding induced abnormal phonon transport in diamondlike structures: Beyond conventional theory
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DOI：
10.1103/physrevb.103.075203
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发表时间：
2021-02
影响因子：
3.7
通讯作者：
Loay Elalfy;D. Music;Ming Hu
中科院分区：
文献类型：
--
作者：
Loay Elalfy;D. Music;Ming Hu
在一些黄铜矿(空间群$i$-42$d$)的例子中出现了一个现象，即较重的原子不一定会导致较低的晶格热导率，这与Kyes公式中的热导率与平均原子质量成反比的表达式相矛盾。在此基础上，从线性化的Boltzmann输运方程出发，利用从头算密度泛函理论，计算并比较了CuIn、CuIn、Se和Te在室温下的导热系数。尽管Te原子明显比Se原子重，但$\mathm{cuin}{\mathm{se}}_{2}$和$\mathm{agin}{\mathm{se}}_{2}$固体的晶格导热系数分别低于$\mathm{cuin}{\mathm{Te}}_{2}$和$\mathm{agin}{\mathm{Te}}_{2}$。通过色散关系、Gr‘uneisen参数和投影态密度的比较，得出结论：以铜和银的反常振动形式存在的非简谐横声波模式导致了较低的导热系数。通过对电子结构的分析，所研究的化合物完全符合最近定义的亚价键的一个区域，该区域以显著的非谐性而闻名。从目前的结果中获得的见解加深了我们对与亚价键有关的异常热传递现象的理解，并为设计和发现打破传统理论预测的热功能材料提供了启示。
A phenomenon appears in a few examples of the chalcopyrites (space group $I$-42 $d$) where heavier atoms do not necessarily lead to lower lattice thermal conductivity, in contradiction with Keyes expression that formulates an inverse relation of thermal conductivity with mean atomic mass. Herewith, the thermal conductivity of $\mathrm{CuIn}{\mathrm{Se}}_{2}, \mathrm{CuIn}{\mathrm{Te}}_{2}, \mathrm{AgIn}{\mathrm{Se}}_{2}$, and $\mathrm{AgIn}{\mathrm{Te}}_{2}$ was calculated and compared at room temperature from the linearized Boltzmann transport equation using ab initio density functional theory. $\mathrm{CuIn}{\mathrm{Se}}_{2}$ and $\mathrm{AgIn}{\mathrm{Se}}_{2}$ solids exhibit lower lattice thermal conductivity than that of $\mathrm{CuIn}{\mathrm{Te}}_{2}$ and $\mathrm{AgIn}{\mathrm{Te}}_{2}$, respectively, despite the fact that Te atoms are significantly heavier than Se. A comparison between dispersion relation, the Gr\"uneisen parameter, and projected density of states leads to the conclusion that anharmonic transverse acoustic modes in the form of anomalous vibrations of Cu and Ag cause the lower values of the thermal conductivity. By analyzing the electronic structure, the compounds under study fit perfectly into a recently defined region of the metavalent bonding well known for its pronounced anharmonicity. The insight gained from the current results deepens our understanding of the unusual heat transfer phenomenon related to the metavalent bonding and sheds light on design and discovery of thermally functional materials that break the prediction by the conventional theory.