Topological phases in few-layer silicene nanoribbon induced by normally applied electric field and Rashba spin-orbit coupling

Abstract

Edge states of a few-layer silicene nanoribbon (FSNR) have potential applications in spintronic and nanodevices. Quantum transport properties of zigzag superlattice FSNR exposed to vertical electric field and Rashba spin-orbit coupling (RSOC) are studied within the tight-binding based non-equilibrium Green's function approach. In addition, the topological insulator-band insulator phase transition of FSNR and the influence of adding a new layer on edge states of conduction electrons have been investigated. Calculations demonstrate that the external electric field applied perpendicularly to the FSNR device, results in gap opening and metal-semiconductor and metal-semimetal phase transition. Further, we found that different topological phase transitions, quasi-topological insulator-band insulator and topological insulator-band insulator by applying a vertical electric field. Meanwhile, results reveal that by tuning the RSOC strength, we can control the spin current. This controllability of spin and quantum transport in FSNR may contribute to potential applications in silicene-based devices and the development of spintronic.