Novel Vistas in Thermal Transport: Relaxons, Frictions, Viscosities, and Coherences
· Invited
Abstract
We examine the emergence of correlated transport phenomena in systems described by the linearized Boltzmann transport equation (LBTE), with examples then centered around heat transport. First, we show how phonons, traditionally considered the carriers of heat, are only a high-temperature approximation to the exact carriers, that we term relaxons, showing how thermal conductivity can be mapped exaclty into a kinetic theory of the relaxon gas, and where the effect of boundaries can be understood in terms of frictions. Second, we show how the LBTE admits coherent propagating solutions with well defined wavevectors and lifetimes, of which second sound is a special case. Last, we discuss generalizations towards the Navier-Stokes continuum, and towards disordered materials. Work performed in collaboration with Andrea Cepellotti (UC Berkeley), Michele Simoncelli (EPFL), and Francesco Mauri (Sapienza U. of Rome).
*This research was supported by the Swiss National Science Foundation through Project ID 200021_143636 and the National Centre of Competence in Research MARVEL.
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Presenters
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Nicola Marzari
- Materials Science & Engineering, École polytechnique fédérale de Lausanne
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne,
- Ecole polytechnique federale de Lausanne
- EPFL STI IMX THEOS, Ecole polytechnique federale de Lausanne
- Theory and Simulation of Materials (THEOS), École Polytechnique Fédérale de Lausanne
- THEOS, Ecole Polytechnique Federale de Lausanne
- Theory and Simulation of Materials, École Polytechnique Fédérale de Lausanne, Switzerland