Quantum Matter Seminar

Moiré superlattices formed by angle-aligned stacks of 2D materials have recently become a rich platform to discover novel electronic states, such as superconductivity, correlated insulators, magnetism, and topological states. In this talk, I will discuss our recent work on the study of correlated states in moiré superlattices of semiconducting transition metal dichalcogenides (TMD) mono- and multi-layers. We employ scanning microwave impedance microscopy (MIM) to probe the local conductivity of these moiré superlattices. We find that correlated insulating states can appear when the moiré superlattice is partially filled with carriers at simple fractional fillings. When additional layers are introduced in the moiré structure, we find that the correlated states can be manipulated in various ways. By applying an electric field, the carriers can be driven to populate two different layers yet still form insulating states. The nature of the correlated states depends on the specific carrier configuration, which we characterize by a combination of optical spectroscopy and scanning probe microscopy measurements. Our results demonstrate the TMD moiré system as a rich platform to explore correlation-enabled electronic phases and showcase the capability of the MIM technique to probe emergent physics in 2D quantum systems.