吕昕，上海科技大学

报告摘要:

Moiré superlattices host a wide range of correlated topological phases, including interaction-driven integer and fractional Chern insulators. Interacting ground states at integer fillings are often studied using Hartree–Fock mean-field theory, but this approach neglects dynamical correlations. As a result, it can overestimate spontaneous symmetry breaking and fails to provide quantitative single-particle excitation spectra.

In this talk, I present a general many-body perturbation framework for moiré systems that goes beyond mean field. The approach combines all-band Hartree–Fock calculations with correlation energies from the random phase approximation (RPA) and quasiparticle corrections from the GW approximation. We apply the framework to hexagonal boron nitride–aligned rhombohedral pentalayer graphene and magic-angle twisted bilayer graphene. Incorporating RPA correlation energies and GW corrections produces phase diagrams and single-particle spectra in quantitative agreement with experiments. This versatile framework offers a systematic beyond-mean-field route for studying generic moiré materials.

Ref: arXiv:2509.19764, arXiv:2512.07115

报告人简介:

Dr. Xin Lu is a Research Assistant Professor （助理研究员） at ShanghaiTech University, working in collaboration with Prof. Jianpeng Liu. He completed his undergraduate studies at école Polytechnique (France) in 2016, received an M.S. in Condensed Matter Physics from école Normale Supérieure (Paris) in 2018, and earned a Ph.D. in Physics from Université Paris-Saclay in 2021. From 2022 to 2024, he was a postdoctoral scholar at ShanghaiTech University with Prof. Jianpeng Liu, and he subsequently joined ShanghaiTech University. His research focuses on condensed-matter theory, particularly twisted and topological materials, as well as magneto-optics. His work has appeared in journals including PRL, PRX, Nature Communications, Nature Materials, and Nature Nanotechnology etc.

邀请人：杨威特聘研究员

联系方式：82648050

地点：物理所M楼253会议室