Effect of strain on the thermoelectric properties of three-dimensional PtS2: A first-principles study

The effect of strain on the electronic structure and thermoelectric properties of three-dimensional (3D) PtS2 was investigated through ab initio calculations. The phonon dispersion curve has no imaginary frequency under biaxial tensile and compressive strains, indicating that the studied structure is stable. All the studied structures show higher Seebeck coefficients (> 400 mu V/K), and the Seebeck coefficient of p-type semiconductors is superior to that of n-type semiconductors. Tensile strain can decrease the lattice thermal conductivity of PtS2, whereas compressive stress has the opposite effect on the lattice thermal conductivity. The smallest lattice thermal conductivity is 26.7 W/m center dot K under 6% strain when the temperature is 800 K. The maximum ZT values for the p-type and n-type semiconductors are 0.17 and 0.48, respectively. This work provides a guide to studying how strain modulates thermoelectric properties of materials; the relaxation time calculation method in this study is believed to be more accurate due to the fact that the influence of the carrier concentration is considered.