報(bào)告題目：Magic flat bands of electrons in moiré graphene

報(bào)告 人：廉骉

報(bào)告時(shí)間：2023年5月12日 9:30

報(bào)告地點(diǎn)：騰訊會(huì)議841 808 309

主辦單位：理學(xué)院

主講人簡(jiǎn)介：Biao Lian received the B.S. degree of Physics in Tsinghua University in 2012 and the Ph.D. degree of Physics in Stanford University in 2017, respectively. He is currently an Assistant Professor with the Department of Physics, Princeton University. His current research interests include 1) Theoretical condensed matter physics: topological states of matter, two-dimensional systems, strongly correlated systems. 2) Nonequilibrium many-body quantum systems: quantum chaos dynamics and thermalization, quantum entanglement.

報(bào)告摘要：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.