Correlation stabilized anomalous Hall crystal in bilayer graphene.

Guo, Zhongqing; Liu, Jianpeng · Nat Commun · 2025

basic_science · Level V

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Abstract

At low carrier densities, interacting electrons can form a Wigner crystal. Rhombohedral multilayer graphene hosts high-order Dirac fermions with nontrivial Berry phases. Using a beyond-mean-field theoretical framework, here we study the ground states of slightly charge-doped rhombohedral multilayer graphene under vertical displacement field. We find a Fermi liquid to trivial Wigner crystal transition at critical densities of ~1-2 × 10<sup>11</sup> cm<sup>-2</sup>, which generally increase with displacement field and layer number. Notably, an anomalous Hall crystal with spontaneous quantized anomalous Hall conductivity emerges at lower densities ~2 × 10<sup>10</sup> cm<sup>-2</sup> and for dielectric constants ϵ<sub>r</sub>⪅5. This topological anomalous Hall crystal is stabilized over the trivial Wigner crystal due to lower correlation energy gained from dynamical charge fluctuations. Our work identifies slightly carrier-doped bilayer graphene as a promising candidate for realizing the anomalous Hall crystal. Moreover, our method can be readily applied to other interacting 2D systems including moiré superlattices.