学术活动
凝聚态
【凝聚态物理-北京大学论坛 2025年第19期(总630期)】Correlated and topological states emerging from rhombohedral multilayer graphene
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主讲人: 刘健鹏 副教授
地点: 物理大楼中212报告厅
时间: 2025年10月9日(周四)下午3:00-4:30
主持 联系人: 叶堉 ye_yu @pku.edu.cn
主讲人简介: 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。此后曾在加州大学圣塔芭芭拉分校卡弗里理论物理研究所和香港科技大学担任博士后和研究助理教授等职位,现为上海科技大学物质学院研究员、长聘副教授。刘健鹏的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开发。近年来在Nature、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。

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 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 lun”, 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:2409.14658 [2] M. Li et al., arXiv:2505.05414

[3] Q. Li et al., arXiv:2505.03891 [4] Y. Shi et al., arXiv:2502.17320