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arXiv · 2003.02384

A generalized decay law for particle- and wave-like thermal phonons

Zhongwei Zhang·Yangyu Guo·Marc Bescond·Jie Chen·Masahiro Nomura·Sebastian Volz
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Abstract

Our direct atomic simulations reveal that a thermally activated phonon mode involves a large population of elastic wavepackets. These excitations are characterized by a wide distribution of lifetimes and coherence times expressing particle- and wave-like natures. In agreement with direct simulations, our theoretical derivation yields a generalized law for the decay of the phonon number taking into account coherent effects. Before the conventional exponential decay due to phonon-phonon scattering, this law introduces a delay proportional to the square of the coherence time. This additional regime leads to a moderate increase in relaxation times and thermal conductivity. This work opens new horizons in the understanding of the origin and the treatment of thermal phonons.

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Zhongwei Zhang, Yangyu Guo, Marc Bescond, Jie Chen, Masahiro Nomura, Sebastian Volz. 2020-03-05. A generalized decay law for particle- and wave-like thermal phonons. https://doi.org/10.1103/physrevb.103.184307

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