First-Principles Prediction of High-Pressure Phase and Thermoelectric Transport in SrAgP

Designing new materials for waste heat to electricity conversion is crucial in energy science. Herein, we have predicted a high-pressure phase of SrAgP, realized above 11 GPa pressure, for thermoelectric applications. Density functional theory (DFT) and hybrid functional (HSE06) are used for a better understanding of the electronic structure and transport properties of the high-pressure phase of SrAgP. A nodal line semimetal (NLSM) phase is observed in DFT calculations, which transform into a trivial band gap phase on using HSE06 hybrid DFT functional. In thermoelectric transport, the maximum value of the dimensionless figure of merit (zT ∼ 0.65) of high-pressure SrAgP is obtained at 800 K in the p-type region. The exciting feature in transport properties is the closely matching zT (∼0.40) values between n-type and p-type regions at 800 K, making high-pressure SrAgP interesting for device-based applications.