Optical detection of Mott and generalized Wigner crystal states in WSe2/WS2 moir\'e superlattices

Understand

Moir\'e superlattices are emerging as a new route for engineering strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states in magic-angle twisted bilayer graphene and ABC trilayer graphene/boron nitride moir\'e superlattices.

• Transition metal dichalcogenide (TMDC) moir\'e heterostructures provide another exciting model system to explore correlated quantum phenomena, with the addition of strong light-matter interactions and large spin-orbital coupling.
• Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moir\'e superlattices.
• Our sensitive optical detection technique reveals a Mott insulator state at one hole per superlattice site ({\nu} = 1), and surprising insulating phases at fractional filling factors {\nu} = 1/3 and 2/3, which we assign to generalized Wigner crystallization on an underlying lattice.