  Transition metal dichalcogenide-based moire superlattices exhibit very strong
electron-electron correlations, thus giving rise to strongly correlated quantum
phenomena such as generalized Wigner crystal states. Theoretical studies
predict that unusual quasiparticle excitations across the correlated gap
between upper and lower Hubbard bands can arise due to long-range Coulomb
interactions in generalized Wigner crystal states. Here we describe a new
scanning single-electron charging (SSEC) spectroscopy technique with nanometer
spatial resolution and single-electron charge resolution that enables us to
directly image electron and hole wavefunctions and to determine the
thermodynamic gap of generalized Wigner crystal states in twisted WS2 moire
heterostructures. High-resolution SSEC spectroscopy was achieved by combining
scanning tunneling microscopy (STM) with a monolayer graphene sensing layer,
thus enabling the generation of individual electron and hole quasiparticles in
generalized Wigner crystals. We show that electron and hole quasiparticles have
complementary wavefunction distributions and that thermodynamic gaps of order
50meV exist for the 1/3 and 2/3 generalized Wigner crystal states.
