Entropic signature of resonant thermal transport: Ordered form of heat conduction

Abstract

Thermal transport in crystals is influenced by chemistry, boundaries, and nanostructure. The anharmonic phonon band structure extracted from molecular-dynamics simulations provides an illuminating view of both the type and extent of prevalence of wavelike mechanisms underlying the transport, yet falls short of elucidating the nature of thermal evolution for different phonon regimes. Here we present an analysis framework for the characterization of the entropic signature of the mechanisms induced by boundaries and nanostructure, using both equilibrium and nonequilibrium atomistic simulations. Specifically, we examine the effects of phonon confinement, Bragg scattering, and local resonances on the configurational phase space in room-temperature nanostructured silicon, and quantify how each modifies the rate of entropy production and thermal relaxation. We reveal that the presence of phonon local resonances spanning the full spectrum enables a highly ordered regime of heat conduction to be approached, where irreversible evolution and entropy maximization are severely hindered by extensive mode hybridizations caused by the resonances. This unique regime of transport paves the way for ultra-precise phonon control for a wide range of applications in condensed matter physics.

References in corpus (8)

• Irreversible entropy production, from quantum to classical
• Towards high-throughput superconductor discovery via machine learning
• Accessing the anisotropic non-thermal phonon populations in black phosphorus
• Non-Fourier heat transport in nanosystems
• Thermodynamic uncertainty relation to assess biological processes
• Universal behavior of highly-confined heat flow in semiconductor nanosystems: from nanomeshes to metalattices
• Semiconductor thermal and electrical properties decoupled by localized phonon resonances
• Resonant phonons: Localization in a structurally ordered crystal