Twisted Bilayer MoS2 under Electric Fields: A System with Tunable Symmetry

Abstract

Gate voltages take full advantage of 2D systems, making it possible to explore novel states of matter by controlling their electron concentration or applying perpendicular electric fields. Here, we study the electronic properties of small-angle twisted bilayer MoS₂ under a strong electric field. We show that transport across one of its constituent layers can be effectively regarded as a two-dimensional electron gas under a nanoscale potential. We find that the band structure of such a system is reconstructed following two fundamentally different symmetries depending on the orientation of the external electric field, namely, hexagonal or honeycomb. By studying this system under magnetic fields, we demonstrate that this duality not only translates into two different transport responses but also results in having two different Hofstadter’s spectra. Our work opens up a new route for the creation of controllable artificial superlattices in van der Waals heterostructures.