arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.04306cond-mat.mtrl-sci
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纳米尺度热输运中声子通道的解纠缠

Disentangling Phonon Channels in Nanoscale Thermal Transport

Samik Mukherjee, Marcin Wajs, Maria de la Mata, Uri Givan, Stephan Senz, Jordi Arbiol, Sebastien Francoeur, Oussama Moutanabbir

摘要:

声子表面散射一直是纳米结构和器件中热输运工程的核心。在这里,我们证明,这种声子途径可以是唯一的机制,只有低于一个特征,尺寸依赖的温度。在此温度以上,晶格声子散射与表面效应共存。通过人工控制纳米线中原子水平的质量无序和晶格动力学,而不影响形态、结晶度、化学组成和电子性质,映射了温度-热导率-直径三参数空间,并解开了主要的声子散射机制。这导致了识别的临界温度,在该温度下,晶格质量无序对热导率的影响被抑制到声子输运完全由表面决定的程度。基于Landauer-Dutta-Lundstrom近平衡输运模型讨论了这一行为。所建立的框架提供了必要的输入,以进一步推进半导体纳米尺度系统中声子和热传输的设计和建模。

英文摘要:

Phonon surface scattering has been at the core of heat transport engineering in nanoscale structures and devices. Herein, we demonstrate that this phonon pathway can be the sole mechanism only below a characteristic, size-dependent temperature. Above this temperature, the lattice phonon scattering co-exist along with surface effects. By artificially controlling mass disorder and lattice dynamics at the atomic-level in nanowires without affecting morphology, crystallinity, chemical composition, and electronic properties, the temperature-thermal conductivity-diameter triple parameter space is mapped, and the main phonon scattering mechanisms are disentangled. This led to the identification of the critical temperature at which the effect of lattice mass-disorder on thermal conductivity is suppressed to an extent that phonon transport becomes governed entirely by the surface. This behavior is discussed based on Landauer-Dutta-Lundstrom near-equilibrium transport model. The established framework provides the necessary input to further advance the design and modelling of phonon and heat transport in semiconductor nanoscale systems.

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