Strain-induced phenomena in layered materials

Using first principles density functional theory (DFT), we investigate the effect of normal compressive strain on the bilayers of MoS2, SnS2, and their van der Waals heterostructure. These materials and the corresponding heterostructure show a universal phenomenon of reversible semiconductor-metal (S-M) transition under applied strain. Most interestingly, a van der Waals heterostructure of MoS2 and SnS2 is found to have an effective direct band gap of 0.71 eV at Γ-point. This inherent ease of tunability of electronic properties of these materials by applying strain or heterostructuring is expected to pave way for further fundamental research leading to multi-physics devices.