Research

2D van der Waals materials can be stacked to create arbitrary heterostructures that exhibit exotic quantum properties. Introducing a relative twist angle between these atomically thin layers creates a spatially varying moiré potential, opening a massive phase space to search for novel correlated states. While these states are traditionally observed via electrical transport, creating reliable Ohmic contacts in semiconducting transition metal dichalcogenides (TMDs) remains a significant challenge. To overcome this, our lab probes these states using novel optical spectroscopy, studying the excitons in the moiré lattice. Because these excitons are sensitive to the dielectric environment, we can optically detect the electronic state. Furthermore, we can design devices to use electrically driven techniques, such as the optical detection of resistance and capacitance (ODRC) technique. We leverage these strong light-matter interactions to map out complex correlated phases, utilizing in situ electric fields to control electron localization and uncover strongly correlated phenomena like Mott insulators and generalized Wigner crystals.

Beyond naturally occurring twisted moiré superlattices, our group is pioneering a versatile platform for designing correlated electronic physics from the bottom up. We create artificial lattices by etching periodic nanopatterns directly into dielectric substrates like SiO$_2$ and hBN. By imposing these periodic potentials onto pristine TMD monolayers, we introduce electrically tunable superlattice potentials that break free from standard moiré geometric constraints. This highly flexible nanopatterning approach allows us to artificially engineer the electronic band structure, aiming to realize interaction-driven topological flat bands and quantum phase transitions. Ultimately, this technique provides a robust, programmable method to explore exotic correlated phases without relying on twist-angle fabrication.