Theoretical insights into the thermoelectric transport performance of the MoP2Ga2S2 monolayer

Abstract

Since the MoSi₂N₄ monolayer was synthesized experimentally, the family of 2D septuple-layer MoSi₂N₄-like materials have attracted widespread attention. However, to date, research on such materials in the thermoelectric field has been rarely reported. In this work, combining first-principles calculations and Boltzmann transport equations, we have investigated the electronic and thermal transport properties of the MoP₂Ga₂S₂ monolayer. The analysis of the phonon spectrum proves that the MoP₂Ga₂S₂ monolayer is dynamically stable. The inherent low thermal conductivity of MoP₂Ga₂S₂ of 0.55 W m⁻¹ K⁻¹ is mainly attributed to the anticrossing behavior of longitudinal acoustic phonons and low-frequency optical phonons, resulting in strong phonon–phonon scattering. The high Seebeck coefficient of 1190 μV K⁻¹ with a high power factor illustrates that MoP₂Ga₂S₂ exhibits excellent electronic transport properties. Furthermore, the increase in temperature promotes the electrical transport while reducing the thermal conductivity. The present work demonstrates that the MoP₂Ga₂S₂ monolayer exhibits excellent thermoelectric performance and provides a new perspective for the research of septuple-layer materials in the thermoelectric field.