Single-layer CdPSe₃: A promising thermoelectric material persisting in high temperatures

Searching for two-dimensional (2D) functional semiconductors with excellent performance is a central issue in the field of 2D materials. Using the first-principles calculation combined with the Boltzmann transport theory, we survey the thermodynamic stabilities, electronic transports, and thermoelectric performances of single-layer (1L-) CdPSe₃, which is a transition-metal phosphorus trichalcogenide. Through an investigation of the cleavage energy, we reveal that an isolation into 1L-CdPSe₃ from the bulk form is guaranteed, which is in addition thermodynamically stable, as confirmed by both the first-principles molecular dynamics and the phonon spectrum. Electron and hole mobilities of 1L-CdPSe₃ are calculated and found to be ∼390 and ∼300 cm² V^-1 s^-1, respectively. The lattice thermal conductivity of 1L-CdPSe₃ is shown to be as low as ∼1.25 W m^-1 K^-1 at room temperature. Finally, the thermoelectric figure of merit of 1L-CdPSe₃ is calculated to be ∼1.2 under the p-type optimal doping at a high temperature (1200 K). This suggests that 1L-CdPSe₃ could be a promising candidate for pursuing an excellent thermoelectric functionality, in particular, valid even at high temperatures.