Ferroelectric switching of superconductivity in magic-angle twisted bilayer graphene

Electrical switching of two-dimensional (2D) superconductivity is critical for nanoscale superconducting circuits including memory elements, rectifiers, and electromagnetic sensing devices. While most field-effect transistors to control superconductivity rely on continuous tuning of carrier density, to date there has not been a bistable switch to turn superconductivity on and off. Recently, researchers uncovered ferroelectricity in Bernal-stacked bilayer graphene aligned to its insulating hexagonal boron nitride (BN) gate dielectrics. Here, we report the observation of similar ferroelectricity in a magic-angle twisted bilayer graphene (MATBG) device with aligned BN layers. This ferroelectric behavior coexists alongside the strongly correlated electron system of MATBG without disrupting its correlated insulator or superconducting states. This all-van der Waals platform enables configurable switching between different electronic states of this rich system. To illustrate this new approach, we demonstrate reproducible bistable switching between the superconducting, metallic, and insulating states of MATBG using gate voltage or electric displacement field. These experiments unlock the potential to broadly incorporate MATBG into highly tunable superconducting electronics.