Single-electron transistor microscopy of correlated states in semiconductor moiré lattices

When two materials with similar lattice constants are stacked with a small interlayer twist, a long-wavelength moiré superlattice develops. This can lead to flat electronic bands which host a variety of interaction-driven phases. Moiré systems composed from semiconducting transition metal dichalcogenides (TMDs) represent an especially flexible platform because the ground states can be tuned by adjusting constituent materials, twist angle, and applied electromagnetic fields. In this talk, I will describe local electronic compressibility measurements conducted with a scanning single-electron transistor that reveal a rich phase diagram of correlated states in twisted TMD systems. We elucidate the spin, valley, and real-space character of the ground states and identify novel excitations. In addition, we demonstrate control over which states are favored by adjusting carrier density and applied electric/magnetic fields. I will discuss how our thermodynamic measurements provide insight into how electronic interactions combine with the underlying nature of the moiré bands to produce multiple distinct regimes of physical behavior.