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[PAST EVENT] Physics Colloquium - Biao Lian

April 21, 2023
4pm - 5pm
Location
Small Hall, Room 111
300 Ukrop Way
Williamsburg, VA 23185Map this location
Access & Features
  • Open to the public
outdoors, outside, trees, flowers, summer, confusion corner, college corner, sign, logo

Biao Lian, Princeton University, Title of talk: "Magic flat bands of electrons in moiré graphene.”

Abstract: The stacking of two similar lattices produces a moiré pattern which is a large spatial period superlattice. Experimentally, a large class of 2D moiré materials can be created using this method, which has attracted extensive interests recently. A paradigm is the twisted bilayer graphene (TBG), which generates topological flat bands of electrons at the so-called magic angle (1.1 degrees), and exhibits superconductivity and correlated insulator phases. I will talk about the systematic theory of TBG with Coulomb interactions, which has an approximate U(4) symmetry and interacting Chern insulator ground states at integer fillings. I will further present alternative setups of moiré models of graphene hosting magic flat bands, such as twisted trilayer graphene, and lattice mismatch moiré graphene systems which exhibits topological flat bands in effective kagome and honeycomb moiré lattices. These systems provide promising platforms for studying novel strongly correlated phases of matter.