Not your familiar two dimensional transition metal disulfide: structural and electronic properties of the PdS2 monolayer

By means of density functional theory (DFT) computations, we theoretically investigated a novel two-dimensional (2D) transition metal disulfide (TMD), namely the PdS2 monolayer. Distinguished from other 2D TMDs which adopt the ordinary 2H or 1T configuration, the PdS2 monolayer presents rather unique structural properties: each Pd atom binds to four S atoms in the same plane, and two neighboring S atoms can form a covalent S-S bond. The hybrid HSE06 DFT computations demonstrated that the PdS2 monolayer is semiconducting with an indirect band gap of 1.60 eV, which can be effectively reduced by employing a uniaxial or biaxial tensile strain. Especially, PdS2 has rather large hole and electron mobilities. Our results suggest that the PdS2 monolayer is rather promising for future electronics and optoelectronics.