Strain-modulated Rashba spin splitting and optical absorption of MoSSe/WSe _2 heterostructures

Effective modulation of electronic and optical properties for van der Waals heterostructures is beneficial to spintronics and optoelectronic devices. We use first-principle calculations to investigate the effects of intralaminar biaxial strain on the Rashba spin splitting and optical absorption of MoSSe/WSe _2 heterostructures. First, considering the different stacking manners, the most stable configuration is confirmed from six heterostructures. The results show that this is in type II energy band alignment, which effectively reduces the carrier recombination rate. Second, Rashba splitting strength can be effectively modulated by biaxial strain, and splitting occurs at the Γ point, in which the tensile and compressive strains can suppress and promote the strength, respectively. Third, we calculate the dielectric constant and optical absorption of the MoSSe/WSe _2 heterostructure and find a higher optical absorption coefficient in visible light scope than two monolayers, and the maximum value can reach 6.11 × 10^5 cm ^-1 . The first absorption peak of the heterostructure increases with increasing tensile strain and the absorption edge is red shifted. On the contrary, there is an opposite effect under compressive strain. These results suggest that MoSSe/WSe _2 heterostructures have potential applications in strain-tunable spintronic and optoelectronic devices.