Thermoelectric transport properties of XAgP (X = Sr and Ba) from first principles

For thermoelectric applications those materials are of interest that have significant power factor (PF) and low lattice thermal conductivity,κL. Here we theoretically exploreκLof two novel materials SrAgP and BaAgP using linearized Boltzmann transport equation with a single-mode relaxation time approach. We estimate the figure of meritzTby employingab-initiocalculations based on density functional theory and semiclassical Boltzmann transport theory. It is observed that at room temperature SrAgP exhibits slightly higher lattice thermal conductivity than BaAgP, which is mainly due to the large phonon group velocity. The relaxation time derived from deformation potential theory indicates a higherp-type PF for SrAgP compared to BaAgP over the entire temperature range. This provides an estimate for the figure of merit for the two materials. The low lattice thermal conductivity and higher PF make SrAgP a more promising thermoelectric material.