1 research outputs found
Optical Sensing of Fractional Quantum Hall Effect in Graphene
Graphene and its heterostructures provide a unique and
versatile
playground for explorations of strongly correlated electronic phases,
ranging from unconventional fractional quantum Hall (FQH) states in
a monolayer system to a plethora of superconducting and insulating
states in twisted bilayers. However, the access to those fascinating
phases has been thus far entirely restricted to transport techniques,
due to the lack of a robust energy bandgap that makes graphene hard
to access optically. Here we demonstrate an all-optical, noninvasive
spectroscopic tool for probing electronic correlations in graphene
using excited Rydberg excitons in an adjacent transition metal dichalcogenide
monolayer. These excitons are highly susceptible to the compressibility
of graphene electrons, allowing us to detect the formation of odd-denominator
FQH states at high magnetic fields. Owing to its submicron spatial
resolution, the technique we demonstrate circumvents spatial inhomogeneities
and paves the way for optical studies of correlated states in optically
inactive atomically thin materials