Heterobilayer with Ferroelectric Switching of Topological State
Jun‐Jie Zhang, Dongyang Zhu, Boris I. Yakobson
Abstract
The realization of multifunctional nanomaterials is both fundamentally intriguing and practically appealing to be used in nanoscale devices. Here, a heterobilayer consisting of realistic 2D-material components of matching lattice symmetry, that is, one being the β-phase antimonene β-Sb known for its strong spin–orbit coupling and ferroelectric In2Se3 monolayer, is designed and explored with first-principles density functional theory. The ferroelectric polarization of the In2Se3 layer induces distinctly different electronic properties in the bilayer. With polarization directed “inward”, the bilayer is a trivial insulator with spatially-indirect band gap (potentially beneficial for photovoltaics). Surprisingly, when polarized “outward”, the bilayer displays nontrivial topological state, Z2 = 1. This suggests that the external electric field can reversibly switch between these two states, inviting potential applications in future multifunctional devices.