Photonic properties of monolayer ZrS₂, PtSe₂ and ZrS₂/PtSe₂ van der Waals heterojunctions under shear strain: a first-principles study

This paper uses first-principles calculations to investigate the electronic and optical properties of single-layer ZrS 2 , PtSe 2 and ZrS 2 /PtSe 2 heterostructures under shear strains in the x–y and y–x directions. The structural stability was confirmed by phonon spectrum and formation energy calculations, and the lowest-energy stacking configuration of the heterostructure was selected for further analysis. Results show that the heterostructure has a lower intrinsic band gap and superior band gap control compared to single-layer materials, especially under 6% shear strain, where the band gap reduces to near zero, exhibiting semimetallic or metallic properties. The II-type band alignment aids photogenerated carrier separation. Optical analysis reveals stronger absorption in the high-energy region, with strain-induced shifts and enhanced low-energy light response. Reflectance spectra show significant anisotropic optical responses. In conclusion, the ZrS 2 /PtSe 2 heterostructure offers significant advantages for optoelectronic devices, infrared detection, and flexible electronics.