Imaging Correlated Quantum Phases in van der Waals Heterostructures

Van der Waals heterostructures of atomically thin crystals offer an exciting new platform to design flat electronic bands for novel correlated quantum phases. We systematically study the flat band and associated correlated states in WS2/WSe2 moire heterostructues using scanning tunneling microscopy (STM). We reveal that three-dimensional lattice reconstruction plays a key role in determining the flat moire minibands in the WS2/WSe2 heterostructure. We further probe correlated electron physics in transition metal dichalcogenide heterostructures, including imaging generalized Wigner crystal states in the WS2/WSe2 moire superlattice and the Wigner crystal states in monolayer WS2.