Thermally stable quantum Hall effect in a gated ferroelectric-graphene heterostructure.

The quantum Hall effect is widely used for the investigation of fundamental phenomena, ranging from topological phases to composite fermions. In particular, the discovery of a room temperature resistance quantum in graphene is significant for compact resistance standards that can operate above cryogenic temperatures. However, this requires large magnetic fields that are accessible only in a few high magnetic field facilities. Here, we report on the quantum Hall effect in graphene encapsulated by the ferroelectric insulator CuInP2S6. Electrostatic gating of the graphene channel enables the Fermi energy to be tuned so that electrons in the localized states of the insulator are in equilibrium with the current-carrying, delocalized states of graphene. Due to the presence of strongly bound states in this hybrid system, a quantum Hall plateau is observed over a wide range of temperatures in relatively modest magnetic fields. The quantum Hall effect has had a profound impact on solid-state physics and has been investigated using different two-dimensional systems, including graphene. Here, the authors investigate graphene encapsulated by a ferroelectric insulator, CuInP2S6, where they observe a quantum Hall effect that endures over a wide temperature range in relatively modest magnetic fields. [ABSTRACT FROM AUTHOR]