报告题目：Correlated and topological states emerging from rhombohedral multilayer graphene

报 告 人: 刘健鹏，上海科技大学

报告时间：2025年11月7日10：00

报告地点：物理楼W218

内容摘要：In this talk, we will discuss correlated and topological states emerging from slightly carrier doped rhombohedral multilayer graphene (RMG) systems. First, we develop a beyond-mean-field theoretical framework to study the Winger-crystal transition problem in slightly charge-doped RMG [1]. Notably, we find that bilayer graphene may be a promising candidate to realize the peculiar anomalous Hall crystal state, which is predicted to be the interacting ground state when the carrier density is below ∼ 2 × 1010 cm−2. Counter intuitively, such topological anomalous Hall crystal becomes more stable than the trivial Wigner crystal due to the lower correlation energy gained from dynamical charge fluctuations [1]. Second, we consider RMG in the “transdimensional regime”, the thickness of which is much larger than a single atomic layer, yet smaller than or comparable to vertical mean free path. In this regime, we report the discovery of a new class of bulk Fermi surface structure with unprecedented low symmetry, the Fermi lune, with peculiar crescent shaped Fermi energy contours [2]. This emergent Fermi lune state driven by electron-electron interactions spontaneously breaks time-reversal, mirror, and rotational symmetries, leading to two distinctive phenomena: giant intrinsic non-reciprocity in longitudinal transport and a new type of magnetism termed “transdimensional orbital magnetism” [2]. The latter is manifested as a fundamentally new type of anomalous Hall effect that exhibits hysteretic responses to in-plane magnetic fields [3]. Lastly, if time allows, I will discuss fractional topological states emerging from RMG coupled with kagome patterned dielectric superlattice [4].

[1] Z. Guo, J. Liu, arXiv:2409.14658v3

[2] M. Li et al., arXiv:2505.05414

[3] Q. Li et al., arXiv:2505.03891

[4] Y. Shi et al., arXiv:2502.17320

报告人简介：刘健鹏于2010年本科毕业于南开大学，2015年获得罗格斯大学博士学位。2015-2020年在加州大学圣芭芭拉分校卡弗里理论物理研究所、香港科技大学等机构任职，现为上海科技大学物质学院研究员、长聘副教授。研究方向为理论与计算凝聚态物理，主要包括但不限于：低维量子材料、莫尔超晶格和异质结中的关联效应与拓扑性质，新型量子材料的磁电、压电和非线性光学特性，以及多体计算方法的发展。近年来在Nature、Science、Nature Materials、Nature Nanotechnology、PRL/PRX、Nature Communications等期刊发表论文约70篇，并主持科技部重点研发计划（青年）项目、基金委面上项目等。