Electrical tuning of helical edge states in topological multilayers

T. Campos, M. A. T. Sandoval, L. Diago-Cisneros, G. M. Sipahi

Published 2019-03-07Version 1

A mainstream within topological insulators, GaSb/InAs quantum wells present a broken gap alignment for the energy bands which supports the quantum spin Hall insulator phase and forms an important building block in the search of exotic states of matter. Such quantum wells have electrons and holes confined in different layers, leading to a wide range of possibilities to tune the topological properties. In this work, using a full 3D 8-band ${\bf k}\cdot{\bf p}$ method, we study the inverted band structure of GaSb/InAs multilayers under the influence of an electric field applied along the growth direction. By tuning the electric field we change the energy levels of both conduction and valence bands, inducing a topological phase transition in the multilayers. We found that the edge states are predominantly confined in the GaSb layer. Our comprehensive characterization of GaSb/InAs multilayers creates a basis plataform uppon which further otimizations of III-V multilayers can be contrasted with.