RQMP Research Seminar

Elucidating the different regimes of phonon transport

Samuel Huberman

Chemical Engineering
McGill University

Thermal processes are ubiquitous across all scales of space and time. Work done in the last decade has led to a number of experimental and theoretical advances that have enabled scientists and engineers to construct an accurate picture of phonon transport at small length and time scales. We will discuss these advances in the context of a few case studies. First, we experimentally and theoretically examine deviations from the diffusive regime of thermal transport in SiGe alloys, thereby extending current theory and experiment to the study of size effects in thermal transport to bulk materials in the transient grating geometry. Additionally, we go beyond the single mode approximation to the Boltzmann transport equation and develop a formalism to study size effects and phonon hydrodynamics by solving the full scattering matrix version of the linearized Boltzmann transport equation. Using this formalism as a guide, we report the experimental observation of second sound in graphite.