Engineered electron crystals in monolayer MoSe₂ via nano-scale gate patterning

In two-dimensional electron systems at low temperatures, electrons can organize into a crystalline state known as a Wigner crystal. Wigner crystals have recently been reported in twisted transition metal dichalcogenide semiconductors where a periodic moiré potential is used to further stabilize the crystal. These generalized Wigner crystals are often still constricted by the fixed triangular geometry of moiré potentials. In our work, we take an alternative approach where a lattice is etched into an integrated graphene gate to create a customizable periodic electronic potential. By etching ~ 40 nm triangular lattices into the top gates of an MoSe₂ heterostructure, we enable a gate-tunable periodic potential and observe evidence of generalized Wigner crystals at near record high charge densities and temperatures of 2Χ10¹² cm^-2 and T = 15 K respectively. The integration of a customizable gate opens pathways to engineer previously unattainable programmable quantum states.