Strain-modulated mechanical, electronic, and thermal transport properties of two-dimensional PdS₂ from first-principles investigations

Strains can effectively modulate the electronic structure and thermal conductivity of materials. In this work, the electronic structure and thermal conductivity properties of PdS₂ under different strains were investigated using first-principles calculation combined with iterative method for solving Boltzmann transport equation theory. Through phonon spectrum calculations, it is found that PdS₂ is thermodynamically stable in the strain range from 0 to 10%. Interestingly, the strained single-layer PdS₂ transforms from an indirect bandgap semiconductor to a quasi-direct bandgap semiconductor, and the bandgap of PdS₂ decreases to 1.41 eV (decreased by 20.8%). Due to the softening of the phonons and the decreasing of phonons group velocity, the thermal conductivity is reduced with the applied biaxial area strains. Thermal transport investigations reveal that the in-plane thermal conductivity of unstrained PdS₂ is 32.32 Wm^− 1 K^− 1. When the area strain reaches 10%, the thermal conductivity of PdS₂ is reduced by nearly twice the ratio of strain. The sensitive strain dependence of bandgap and thermal conductivity indicates that PdS₂ can flexibly select the substrate and match the substrate, and the thermoelectric coefficient can be effectively adjusted, indicating that PdS₂ has good application prospects in thermoelectric, photoelectric, and catalytic materials.