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Host: Prof. Haibiao Zhou
Venue: TDLI Meeting Room N601
Tencent Meeting link: https://meeting.tencent.com/dm/6PlgqI9LUnVo
Meeting ID: 223664449, no password
Abstract:
Topological flat bands, characterized by flat electronic dispersion and nontrivial topology, are of fundamental importance in condensed matter physics, providing a theoretical platform for exploring exotic quantum states such as unconventional superconductivity and the quantum anomalous Hall effect. In rhombohedral multilayer graphene, the low-energy electronic bands exhibit a layer-dependent power-law dispersion, combining pronounced flat-band character with strong Berry curvature. Crucially, the band structure and Berry curvature distribution can be continuously tuned by an external electric field, offering an ideal platform for realizing correlated topological states including tunable quantum anomalous Hall effects. In this talk, we will discuss how moiré superlattices introduced via heterojunctions or homojunctions can be used to engineer isolated surface flat bands in rhombohedral multilayer graphene, and how this platform has enabled the observation of novel quantum phenomena such as interlayer-polarized ferromagnetic states, chirality-tunable Chern insulator states, and high-Chern-number quantum anomalous Hall states.
Biography:
Dr. Shuigang Xu is currently an Assistant Professor in department of Physics at Westlake University. He received his B.S. from Wuhan University in 2009 and his Ph.D. in physics from the Hong Kong University of Science and Technology in 2013. After his doctoral studies, he continued as a postdoctoral researcher in the same group before joining the Condensed Matter Physics Group at the University of Manchester, UK, in 2016. In September 2021, he joined the Department of Physics at Westlake University, where he established the 2D Materials and Quantum Transport Laboratory. Dr. Xu's group has been engaged in the synthesis of two-dimensional materials, investigation of quantum transport properties, and development of van der Waals heterostructure-based devices. Recently, his group has achieved a series of advances in strongly correlated effects, topological states, and unconventional ferroelectricity in two-dimensional materials.