Theoretical insight into potential thermoelectric performance of ternary metal phosphide CaAgP

Metal phosphides have recently emerged as promising thermoelectric materials with high performance and low cost of constituent elements. In this work, we provide atomistic insight into thermoelectric performance of ternary metal phosphide CaAgP using first-principles calculations of transport properties, focusing on an accurate description of phonon–phonon and electron–phonon interactions. Applying a unified theory for lattice thermal conductivity and momentum, self-energy relaxation time approximation approaches for phonon-limited electronic transports result in overall agreement with experiment for transport properties of CaAgP. Having a promising thermoelectric figure of merit ZT over 0.48 at 650 K, nano-phasing or doping is suggested to further enhance the thermoelectric performance.