  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 can be achieved at room temperature in relatively modest magnetic
fields. This phenomenon offers the prospect for the controlled manipulation of
the quantum Hall effect at room temperature.
