Mott insulator is a central concept in strongly correlated physics and manifests when the repulsive Coulomb interaction between electrons dominates over their kinetic energy. A tunable Mott insulator, where the competition between the Coulomb interaction and the kinetic energy can be varied in situ, can provide an invaluable model system for the study of Mott physics. In this talk, I will discuss a general route to engineer strongly correlated physics in two-dimensional moiré superlattices, and show the experimental realization of a tunable Mott insulator in the ABC stacked trilayer graphene (TLG)/hBN moiré superlattice. The moiré superlattice in TLG/hBN heterostructures leads to narrow electronic minibands and allows for the observation of gate-tunable Mott insulator states at 1/4 and 1/2 fillings. Interesting signatures of superconductivity are observed at low temperature near the 1/4 filling Mott insulating state in the TLG/hBN heterostructures. A topological Chern insulator with Chern number C = 2 and ferromagnetism are experimentally observed in the non-trivial band in trilayer graphene system, which makes it possible to study Mott, superconductivity and topological physics in one system.

陈国瑞，加州大学伯克利分校博士后。2010年本科毕业于山东大学物理与微电子学院，2016年博士毕业于复旦大学物理系并留校任博士后，2017年至今为美国加州大学伯克利分校物理系博士后。研究兴趣主要在高质量二维材料及其范德瓦尔异质结，尤其是石墨烯的强关联和拓扑效应的量子输运。近年来在Nature, Nature Physics, Nature Materials, Nature Nanotechnology, PRL和Nano Letters等杂志期刊发表十多篇文章，被引用1000多次。