Novel two-dimensional PdSe phase: A puckered material with excellent electronic and optical properties

By combining structural search and first-principles calculations, we predict a new stable two-dimensional PdSe monolayer, and systematically investigate its structural, electronic and optical properties. The calculated formation enthalpy, phonon spectra and molecular dynamic simulations confirm that PdSe monolayer possesses excellent thermodynamic and dynamic stability. PdSe monolayer is a semiconductor with an indirect band gap of ∼ 1.10 eV. The carrier transport of PdSe monolayer is dominated by hole and exhibits remarkable anisotropy due to the intrinsic structure anisotropy. The optical properties also show obvious anisotropic characteristic with considerable absorption coefficient and broad absorption from the visible to ultraviolet regions. Benefiting from these excellent physical properties, PdSe monolayer is expected to be a promising candidate as electronic and optoelectronic devices.