The Reversible and Nonvolatile Properties of 2D LaBr2/α-In2Se3 Heterostructure by Strain and Electric Field Modulation

Abstract

Two-dimensional 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 firstprinciple 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 up state. By switching the ferroelectric polarization of α-In2Se3, the heterostructure undergoes the 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 nonvolatile 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.

Keywords: first principle, Ferroelectric, vdW heterostructure, valleytronics