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

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.

arXiv comment5 pages, 5 figures, 1 Supplementary Material

References in corpus (9)

• Optimized Tersoff and Brenner empirical potential parameters for lattice dynamics and phonon thermal transport in carbon nanotubes and graphene
• Unified theory of thermal transport in crystals and disordered solids
• Efficient molecular dynamics simulations with many-body potentials on graphics processing units
• Modeling heat transport in crystals and glasses from a unified lattice-dynamical approach
• Heat conduction tuning using the wave nature of phonons
• Thermal transport in crystals as a kinetic theory of relaxons
• Lifetimes of Confined Acoustic Phonons in Ultra-Thin Silicon Membranes
• Phonon Coherence and Its Effect on Thermal Conductivity of Nanostructures
• Phonon nanocapacitor for storage and lasing of terahertz lattice waves

Cited by in corpus (5)

• GPUMD: A package for constructing accurate machine-learned potentials and performing highly efficient atomistic simulations
• Heat conduction theory including phonon coherence
• Phonon coherence and minimum thermal conductivity in disordered superlattice
• Assessing Phonon Coherence Using Spectroscopy
• Influence of Spatial Coherence on Phonon Transmission across Aperiodically Arranged Interfaces