Ex-situ modification of lattice thermal transport through coherent and incoherent heat baths
Ex-situ modification of lattice thermal transport through coherent and incoherent heat baths
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DOI：
10.1016/j.mtphys.2022.100884
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发表时间：
2022-10
影响因子：
11.5
通讯作者：
Tengfei Ma;Yan Wang
中科院分区：
文献类型：
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作者：
Tengfei Ma;Yan Wang
目前用于定制材料的热导率的大多数策略直接修改材料的组成或结构，例如，通过合金化或修改微观结构。在这项工作中，我们证明了异位修改的热导率的设备包含二次周期性通过合理选择的热浴。分子动力学模拟表明，相干浴，其中的声子透射谱与设备相匹配，可以大大提高Lennard-Jones（高达400%）和硅/锗（高达40%）超晶格器件的热导率时，与非相干浴的情况相比。声子传输计算揭示了强烈的相干-非相干声子非平衡附近的设备和非相干浴之间的界面，这一点，所阐明的建议的相干-非相干声子传输模型，阻碍热传输。这项工作提供了一种策略，大大定制纳米器件的非原位的热导率，而不需要不可逆地修改设备的结构或组成。
Most of the current strategies for tailoring the thermal conductivity of materials directly modify the composition or structure of a material, for instance, by alloying or modifying the microstructure. In this work, we demonstrate the ex-situ modification of thermal conductivity of devices containing secondary periodicity through the rational choice of heat baths. Molecular dynamics simulations show that coherent baths, of which the phonon transmission spectrum matches with that of the device, can greatly increase the thermal conductivity of Lennard-Jones (up to 400%) and silicon/germanium (up to 40%) superlattice devices, when compared with the cases of incoherent baths. Phonon transmission calculations reveal strong coherent-incoherent phonon nonequilibrium near the interface between the device and incoherent baths, which, as elucidated by a proposed coherent-incoherent phonon transport model, hinders thermal transport. This work provides a strategy to greatly tailor the thermal conductivity of nanodevices ex-situ without the need to irreversibly modify the structure or composition of the device.