Strain and field-tunable electronic and optical properties of van der Waals heterostructures

Layered materials (LMs) have gained attention becuse of their properties and potential application in ferroelectric devices, optoelectronics, and energy conversion and storage. In this study, we constructed the SnSe/PbSe heterostructures, one ferroelectric and other non ferroelectric monolayers, using first principles density functional theory. The results show indirect to direct bandgap transition under biaxial strain and semiconductor-to-metallic transition under external electric field strength. Due to interlayer charge redistribution and lattice distortion, the heterostructure exhibits spontaneous in-plane polarization, enhanced compared to its constituent monolayers. Biaxial strain tunes and enhances the absorption coeffienct while the applied electric fields show negligible effects. The results show that strain and electric field engineering are effective techniques for modulating ferroelectric performance in 2D heterostructures and advancing their integration into next-generation nanoelectronic devices.