Speaker
Description
In this talk, we discuss correlated topological states emerging in bilayer-graphene-based superlattices. First, we develop a beyond-mean-field theoretical framework to investigate Wigner crystallization in lightly doped rhombohedral multilayer graphene (RMG) [1]. Notably, we find that bilayer graphene may provide an ideal platform for realizing an exotic anomalous Hall crystal state, which is predicted to be the interacting ground state at carrier densities below ～2×10^10 cm-2. Counterintuitively, this topologically nontrivial anomalous Hall crystal is more stable than the topologically trivial Wigner crystal because dynamical charge fluctuations yield a greater reduction in its correlation energy [1]. Furthermore, by coupling bilayer graphene to patterned dielectric superlattices, we find that robust fractional topological states can emerge, including both Abelian [2] and non-Abelian [3] states. In particular, we develop a gradient-based device-design framework that optimizes experimentally tunable structural parameters to obtain ideal energy bands for hosting non-Abelian topological order. Using this approach, we numerically realize non-Abelian Moore–Read fractional Chern insulator states in triangular, honeycomb, and kagome patterned superlattices over broad regions of the parameter space spanned by the superlattice period and the out-of-plane potential drop [3].
[1] Z. Guo and J. Liu, Nat. Commun. 16, 11289 (2025).
[2] Y. Shi et al., Phys. Rev. Lett. 135, 256603 (2025).
[3] Y. Guan et al., arXiv:2608.09245.