Speaker
Description
The thermal properties of materials are important for the development of various modern technologies. In particular, thermoelectric energy conversion and thermal barrier require materials with ultra-low thermal conductivity. Lattice vibration dominates heat transport in insulating solids; recent theoretical studies suggested that both propagation and diffuson-like behaviors of phonons can play a critical role when the phonon mean free path is close to the atomic distance. In this presentation, I will discuss abnormal thermal transport behaviors in complex argyrodite compounds and our theoretical insight into the phenomena. Based on the more in-depth understanding, we propose alternative principles to explore fully dense crystalline solids with ultra-low thermal conductivities. We performed our research based on the thermal transport unified theory, first-principles calculations of anharmonic lattice dynamics, and machine-learned interatomic potentials. This presentation will focus on discussing nonconventional phonon transport mechanisms in technologically important solids.
