Quantum Foundry Seminar: Hongyuan Li

"Imaging Interacting Electrons in van der Waals Moiré Heterostructures"

Abstract:

Van der Waals heterostructures of atomically thin crystals offer an exciting new platform to design flat electronic bands for novel quantum phases. We systematically study the flat band and associated correlated ground states and novel excited states in van der Waals moiré heterostructures using scanning tunneling microscopy (STM). We reveal that three-dimensional lattice reconstruction plays a key role in determining the flat moiré minibands in the WS2/WSe2 heterostructure. We further probe correlated electron physics in transition metal dichalcogenide heterostructures and directly image the generalized Wigner crystal states in the WS2/WSe2 moiré superlattice. We also study the photoexcited states in a twisted WS2 bilayer moiré superlattice through a nanoscale photocurrent measurement and directly resolve a new type of in-plane charge-transfer moiré exciton.

Bio:

Hongyuan is currently a PhD candidate majoring in applied science and technology at UC Berkeley. He obtained his BS degree in physics from Xian Jiaotong University in China in 2017. His research work mainly focuses on experimental condensed matter physics, particularly the strongly correlated electron behavior in low-dimensional materials.