The role of phonon–phonon and electron–phonon scattering in thermal transport in PdCoO2
Abstract
The layered metal oxide PdCoO2 is of fundamental interest in solid-state physics due to its unique nature as a two-dimensional electron gas. It is well known that electron–phonon scattering plays the leading role in the electrical transport of lots of materials; however, the influence of electron–phonon coupling on the thermal transport in PdCoO2 is rarely studied. Herewith we employ ab initio calculations to study the phonon lifetimes of PdCoO2 due to electron–phonon scattering and anharmonic phonon–phonon interactions. It is found that electron–phonon scattering has a large correction to the lattice thermal conductivity of PdCoO2 for both the in-plane and cross-plane directions, which is reduced by 21% and 27%, respectively. Moreover, the correction becomes larger and is more significant for the in-plane direction with decreasing temperature. As a result, the cross-plane lattice thermal transport overwhelms the in-plane value at low temperatures. This study provides useful guidance for the development of relevant devices involving two-dimensional electron gas systems.