Ultralow thermal conductivity of β-Cu2Se by atomic fluidity and structure distortion
Ultralow thermal conductivity of β-Cu2Se by atomic fluidity and structure distortion
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DOI：
10.1016/j.actamat.2014.12.008
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发表时间：
2015-03
期刊：
影响因子：
9.4
通讯作者：
Hyoungchul Kim;S. Ballikaya;H. Chi;J. Ahn;Kiyong Ahn;C. Uher;M. Kaviany
中科院分区：
文献类型：
--
作者：
Hyoungchul Kim;S. Ballikaya;H. Chi;J. Ahn;Kiyong Ahn;C. Uher;M. Kaviany
我们展示了固体中液体导热性的原型热演化路径。β-Cu 2 Se的热演化表现为组成原子的大间隙位移，表现为类玻璃跃迁和渐近液体热输运。利用从头算分子动力学（AIMD），我们确定了这些跃迁，并用原位透射电镜和电子能量损失谱证实了它们。Cu+离子的热无序性在刚性Se框架下形成均极性Cu - Cu键，在更高温度下Se框架发生热畸变。晶格热导率的非平衡AIMD预测显示声子输运受到显著抑制，与实验和分子行为一致。
We demonstrate a prototype thermal evolution path for liquid thermal conductivity in solids. Thermal evolution of β-Cu 2 Se shows large interstitial displacement of constituent atoms marked by glass-like transitions and an asymptotic liquid thermal transport. Using ab initio molecular dynamics (AIMD), we identify these transitions, and confirm them with in situ transmission electron microscopy and electron energy loss spectroscopy. The thermal disorder of the Cu+ ions forms homopolar Cu–Cu bonds under a rigid Se framework, and at yet higher temperatures the Se framework undergoes thermal distortion. The non-equilibrium AIMD prediction of lattice thermal conductivity shows significant suppression of the phonon transport, in agreement with experiments and molecular behavior.