1-9. Thermal Transport in the Materials with Coexisting Order-disorder

Wenqing Zhang, Hongliang Yang
Department of Physics, Southern University of Science & Technology, Shenzhen, China

Abstract: The multi-component or multi-chemical-bond materials with chemical bond hierarchy, exhibiting the part-crystalline part-liquid (PCPL) state, have recently been proposed to be emerging candidate of thermoelectric materials. These materials contain at least two different types of sublattices, one crystalline and another one strongly disordered or even liquid-like, leading to extremely low lattice thermal conductivity. This talk presents a survey on the general characteristics of the thermal transport in the PCPL materials. We developed a molecular dynamics (MD) approach to simulate the complex thermal transport process. The results in Green-Kubo method and Boltzmann transport theory are compared to elucidate the thermal transport mechanism of the PCPL materials by using empirical interatomic potentials fitting to the liquid-like thermoelectrics like Cu2Se. The contribution to thermal transport from each structural component, i.e. the rigid-crystalline, strongly disordered, and/or liquid-like parts, are respectively analyzed. Our recent work also found a few other thermoelectric materials with order-disorder coexistence, in which our work reveals a strong similarity for thermal transports to those in PCPL materials. This talk will also discuss the relationship of the above work to the minimum thermal conductivity.