Tuning the Bandgap and Topological Phase Transition in Bilayer Van der Waals Stanane by Electric Field

Abstract

For very few special 2D materials, electric field can be used to realize the topological phase transition from normal insulator (NI) into topological insulator (TI). To design the low‐power electronic devices based on 2DTIs, tunable and practical 2DTIs may be necessary. Herein, a model of electric field‐tunable 2DTIs based on bilayer van der Waals semiconductors is proposed. The bilayer semiconductors can be tuned by electric field from NIs into TIs. As a good candidate of the predicted 2DTIs, the possible topological phase transition of bilayer stanane (SnH) under electric field using first‐principles calculations is studied. The calculations suggest that bilayer stanane can be converted from NI into TI by vertical electric field. The topological bandgap can be up to about 22.8 meV, which is giant for the electric field‐tunable 2DTIs. It can be further enlarged by vertical pressure. This discovery provides new possibilities for converting NIs into TIs by electric field and creating multifunctional topological field‐effect transistors by tunable 2DTIs.