The reversible and nonvolatile properties of 2D LaBr2/α-In2Se3 heterostructure by strain and electric field modulation

Abstract

Two-dimensional (2D) ferroelectric materials have intrinsic polarized electric field, when they stack with other 2D materials to construct ferroelectric van der Waals heterostructures, they will produce a lot of novel properties, which has aroused extensive research interests. Therefore, based on first-principle calculations, we have comprehensively studied the electronic properties of LaBr2/α-In2Se3 ferroelectric heterostructures to investigate the reversibility and nonvolatility with information. Our calculations show that, the system is a ferromagnetic semiconductor with intrinsic valley polarization when α-In2Se3 is in the ferroelectric polarized up state. By switching the ferroelectric polarization of α-In2Se3, the heterostructure undergoes a transition from semiconductor to half metal, which can be attributed to the competition between the built-in electric field (Eint) and the polarized electric field Epi→,generated by the charge transfer at interface of heterostructure and the bound charge of α-In2Se3, respectively. Besides, the band arrangement types of LaBr2/α-In2Se3 heterostructure can be well modulated under extra electric filed and biaxial strain. Furthermore, we have observed valley-submerging under electric filed and strain, which indicates the valleytronic nature can also be on-off in LaBr2/α-In2Se3 heterostructures. More importantly, the realization of reversible and non-volatile properties depends on the intrinsic characteristics of heterostructure and does not require external mechanisms. Our research not only provides the possibility for the application of the LaBr2/α-In2Se3 heterostructures in nanodevices, but also give the theoretical support to the study of spintronics and valleytronics.