Summary:

Studying the intrinsic behavior 2D materials requires attention to both external and internal sources of disorder. This talk will first review the techniques used to create clean heterostructures with hBN to reduce environmental disorder. In graphene, ten years of progress has led to device performance now rivaling he highest-quality GaAs-based heterostructures. On the other hand, semiconducting transition metal dichalcogenides (TMDs) are also limited by atomic defects within the crystalline layers, which requires efforts in synthesis and characterization of high purity crystals. This talk will present recent progress in synthesis of TMD crystals with dramatically lower defect density using a self-flux technique. Combining higher crystal quality and clean encapsulation allows observation of greatly enhanced optical properties, including near-unity photoluminescence quantum yield, and long excited-state lifetime in TMD heterostructures. In addition, electronic transport measurements show improved carrier mobility and reveal many new details in magnetotransport measurements, including observation of fractional quantum Hall states in monolayer TMDs. These high-quality crystals also allow studies of twisted bilayer TMDs, which show the emergence of many-body correlated states.

James Hone is currently Wang Fong-Jen Professor of Mechanical Engineering at Columbia University, and director of PAQM, Columbia’s Materials Science Research and Engineering Center (MRSEC). He received his BS in physics from Yale in 1990, and PhD in experimental condensed matter physics from UC Berkeley in 1998, and did postdoctoral work at the University of Pennsylvania and Caltech, where he was a Millikan Fellow. He joined the Columbia faculty in 2003.

 

DATE: Thursday, February 4, 2021
TIME: 1:00 pm - 2:00 pm Eastern



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