Computational Investigations of the Lattice Dynamics in SnSe Alloy

Recent experiments revealed that SnSe has an unprecedented ZT value of 2.6±0.3 at 923 K, the highest ZT value reported to date for any thermoelectric system. This finding is extremely encouraging, particularly because of SnSe's simplicity in terms of crystal structure and chemical composition. The remarkably high value achieved is believed to be related to the alloy's intrinsically low thermal conductivity. Understanding the physics of low thermal conductivity could benefit the design of high-performance thermoelectrics. In this project, we will investigate the lattice dynamics in SnSe based on density functional theory and molecular dynamic simulations, which will allow us to have deep insights on the origins of the intrinsically ultra-low thermal conductivity.