Exploring a Novel Atomic Layer with Extremely Low Lattice Thermal Conductivity: ZnPSe3 and Its Thermoelectrics

We survey the thermodynamic stabilities and properties, electronic transports, and thermoelectric possibilities of two-dimensional (2D) ZnPS3 and ZnPSe3, belonging to transition-metal phosphorus trichalcogenides, by employing the first-principles electronic structure calculation. Our first-principles calculation accompanying ab initio molecular dynamics and phonon calculation predicts that a single-layer (1L-) ZnPSe3 would be thermodynamically stable; in addition, electron and hole mobilities of 1L-ZnPSe3 amount to ∼440 and ∼400 cm2 V–1 s–1, respectively, which are comparable to 1L-MoS2. More interestingly, the lattice thermal conductivity of 1L-ZnPSe3 is found to be lower than any other 2D material, which could reach the lowest, i.e., ∼0.13 W m–1 K–1 at room temperature. In contrast, the thermoelectric figure of merit of the pristine 1L-ZnPSe3 is just ∼0.8 under optimal condition. Nevertheless, this is a very promising indication for a thermoelectric application of 1L-ZnPSe3 because other elements to det...