Simulations Guiding Phonon Thermal Conductivity Reductions

Minimizing lattice thermal conductivity has been a goal for engineering enhanced thermoelectric figures of merit for over a decade, both intrinsically (e.g., material choices) and extrinsically (e.g., defects and nanostructuring). In the context of numerical simulations, we discuss phonon scattering details that underlie thermal resistance in bulk, nanostructured, and alloyed materials. We highlight promising routes for decreasing lattice thermal conductivity, limitations on these, and challenges faced in simulations of realistic materials. We use large-scale mass disorder models, temperature-dependent effective potentials, density functional theory, and Boltzmann and Wigner transport methodologies to understand how alloy disorder, temperature renormalization, correlations, and phonon dispersion features govern thermal transport in materials of potential interest for thermoelectric applications.<br/><br/>L.L. acknowledges support from the U. S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.