Thermoelectric Properties of Layered BaFZnP Material in Consideration of Fourth-Order Anharmonicity and Multiple Carrier Scattering Rates: First-Principles Calculations

Layered BaFZnP compound, characterized by a supercell structure with the stacking axis perpendicular to the [Ba 2 F 2 ] 2+ and [Zn 2 P 2 ] 2– layers, has garnered special attention in thermoelectric (TE) materials. In the current work, the crystal structure, thermal and electronic transport properties, and thermoelectric performance of the BaFZnP compound are explored through first-principles calculations and Boltzmann transport theory. The layered BaFZnP compound exhibits a direct band gap of 1.24 eV, featuring band degeneracy in the electronic band structure. Due to the weak interlayer interactions along the out-of-plane direction and correspondingly robust intralayer interactions along the in-plane direction, a low lattice thermal conductivity of 1.99 W/mK is achieved for the BaFZnP compound at 300 K under the consideration of a four-phonon scattering process. Meanwhile, excellent electronic transport performance is also observed in the BaFZnP compound, as demonstrated by the high Seebeck coefficient, the appropriate electrical conductivity, and the high power factor. Within the consideration of four-phonon scattering and multiple carrier scattering rates, a high thermoelectric dimensionless figure of merit ( ZT ) of 1.94 at 900 K is achieved for the BaFZnP compound along the in-plane direction, showcasing the great promising prospect for the p-type thermoelectric material. Our current work not only delves into the fundamental comprehension regarding the electronic and thermal transport properties of the layered BaFZnP compound but also contributes to a deeper understanding of the intrinsic four-phonon scattering and multiple carrier scattering processes in governing the excellent TE performance.