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MSE Seminar: “Interacting Opto-Moiré Quantum Matter” (University of Washington)
March 16, 2023 at 10:30 AM - 12:00 PM
Moiré superlattices of two-dimensional (2D) materials are an emerging platform for studying new physical phenomena with high tunability. Strong excitonic responses in transition metal dichalcogenides (TMDs) allow optical access to the wealth of physics. In this talk, I will present our recent results about interactions between excitons and charge carriers trapped in moiré potentials. We have discovered novel exciton many-body ground states composed of moiré excitons and correlated electron lattices, resulting from new interaction between exciton and charges enabled by unusual quantum confinement in 2D moiré superlattices. The interaction further enriches the magnetic phases in such moiré superlattices. We have observed that the spin-spin interactions between moiré trapped holes can be drastically tuned by optical excitation power. The mechanism points to the unique excitons-mediated long-range exchange interaction between moiré trapped carriers. This discovery adds a new and dynamic tuning knob to the rich many-body Hamiltonian of moiré quantum matter. Our work provides the framework for understanding and engineering electronic and excitonic states in moiré quantum matters.
Xi Wang
Postdoctoral Fellow, Department of Physics, University of Washington
Xi Wang is a Postdoctoral Fellow in the Physics Department at the University of Washington, Seattle, working with Prof. Xiaodong Xu and Prof. Daniel Gamelin. Xi received her B.S. degree in physics from the University of Science and Technology of China (USTC). She then pursued her Ph.D. at Florida State University. She studied a new class of materials, for energy-efficient applications, called hybrid organic-inorganic halide perovskites using microscopy and spectroscopy. She has developed expertise in creating and understanding novel solid-state materials in the aspect of optical, electronic, and magnetic properties. Her current research focuses on designing, fabricating, and characterizing high-quality heterostructures made from two-dimensional (2D) materials. She studies the excitonic-related quantum many-body interactions in moiré superlattices, a class of artificial lattices created by designated stacking of 2D monolayers.