Abstract The thickness dependent in-plane thermal conductivity of layered Tungsten ditelluride (WTe2) is investigated by first-principles calculation. With the layer number increasing from one to infinite, the thermal conductivity displays a decrease to increase trend. The underlying mechanism is attributed to the change of the phonon dispersion relations. As the layer number increases, optical phonon branches shift downward, which provide more channels for the Umklapp scattering, and result in the decrease of the thermal conductivity. Furthering increasing the layer number makes those low-frequency optical phonon branches having high group velocity and leads to the increase of the lattice thermal conductivity.

中文翻译：

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通过第一性原理计算的异常层厚度依赖的 Td-WTe2 热导率

摘要 通过第一性原理计算研究了层状二碲化钨 (WTe2) 与厚度相关的面内热导率。随着层数从一层增加到无限大，热导率呈现降低到增加的趋势。潜在机制归因于声子色散关系的变化。随着层数的增加，光声子分支向下移动，为 Umklapp 散射提供更多通道，导致热导率下降。进一步增加层数使得那些低频光学声子分支具有较高的群速度并导致晶格热导率增加。