Effects of non-metal doping and shear strain on the electronic, optical and magnetic properties of the PtS₂/PtSe₂ van der Waals heterojunction

Abstract This paper investigates the effects of second-period atom doping (N, O, F, Ne) and shear strain on the optoelectronic properties and magnetism of the PtS 2 /PtSe 2 van der Waals heterojunction based on density functional theory. First, we identify the most stable heterostructure by examining the binding energy, and further validate it through phonon dispersion and dynamics. PtS 2 /PtSe 2 exhibits an indirect band gap of 0.49 eV and belongs to type-II band alignment. Doping of N atoms into PtSe 2 layers preserves the band gap value, while inducing significant spin splitting; however, doping into the PtS 2 layer leads to metallic properties, and the differential charge density map shows a substantial increase in charge transfer, providing theoretical guidance for the fabrication of high-performance chips. Similarly, doping N atoms into both layers results in metallic characteristics. The increase in shear strain in both directions uniformly reduces the band gap value but does not induce spin splitting. N-doped structures enhance UV-A absorption; PtSe 2 -layer doping boosts UV-C absorption to 15 × 10 4 cm −1 , rising to 15.54 × 104 cm −1 with 4% x-y shear strain. Increasing x-y strain redshifts the UV-A spectrum to enhance visible absorption; increasing y-x strain blueshifts it to strengthen UV absorption. These findings inform high-performance optoelectronic device development.