Speaker
Description
Understanding thermal transport is of fundamental importance in several technological applications, like transistors, optoelectronics, photovoltaics, and thermoelectrics. Materials with an intrinsic low lattice thermal conductivity (kl) provides a pathway for discovering high zT materials without degrading its charge transport. Lattice expansion is one of the strategies to achieve low kl through phonon softening. In the present study, the effect of lattice expansion on the phonon transport properties of Barium Chalcogenides has been studied. Dynamical stability of these compounds under lattice expansion has been established from the computed phonon dispersion curves. A significant lowering of lattice thermal conductivity (5.63 Wm-1K-1 to 2.06 Wm-1K-1, 6.17 Wm-1K-1 to 2.38 Wm-1K-1, 9.84 Wm-1K-1 to 5.1 Wm-1K-1) for BaO, BaS and BaTe respectively with increasing lattice expansion from 0% to 4% was observed. Microscopic origins for low lattice kl are discussed through phonon scattering and phonon group velocities. Current research could provide insights into how to develop low kl materials by lattice expansion, which is crucial for developing sustainable energy conversion systems for future thermal energy applications.
