Intrinsic layer polarization and multi-flatband transport in non-centrosymmetric mixed-stacked multilayer graphene
Abstract
Graphene multilayers exhibit electronic spectra that depend sensitively on both the number of layers and their stacking order. Beyond trilayer graphene, mixed stacking sequences (alternating Bernal and rhombohedral layers) give rise to multiple coexisting low-energy bands. Here we investigate ABCBC-stacked pentalayer graphene, a less-studied non-centrosymmetric mixed sequence. This stacking can be regarded as an ABC (rhombohedral) trilayer on top of an AB (Bernal) bilayer, so its low-energy band structure contains both a cubic band and a parabolic band that hybridize. In transport measurements, we observe an intrinsic band gap at charge neutrality whose magnitude changes asymmetrically under an applied perpendicular displacement field. This behavior reflects the spontaneous layer polarization inherent to the broken inversion symmetry and mirror symmetry. By tuning the displacement field and carrier density, we drive multiple Lifshitz transitions in the Fermi surface topology and realize Landau levels with different degeneracies arising from the multi-flatband system. Remarkably, a v = -6 quantum Hall state emerges at an exceptionally low magnetic field (~20 mT), indicating the interplay between spontaneous symmetry breaking and Berry curvatures. Our results establish mixed-stacked multilayer graphene as a tunable platform with various broken symmetries and multiple flatbands, suitable for exploring emergent correlated electronic states.
Keywords
Cite
@article{arxiv.2505.12478,
title = {Intrinsic layer polarization and multi-flatband transport in non-centrosymmetric mixed-stacked multilayer graphene},
author = {Kai Liu and Yating Sha and Bo Yin and Hongyun Zhang and Jinxi Lu and Shuhan Liu and Size Wu and Yulu Ren and Zhongxun Guo and Jingjing Gao and Ming Tian and Neng Wan and Kenji Watanabe and Takashi Taniguchi and Bingbing Tong and Guangtong Liu and Li Lu and Yuanbo Zhang and Weidong Luo and Zhiwen Shi and Shuyun Zhou and Quansheng Wu and Guorui Chen},
journal= {arXiv preprint arXiv:2505.12478},
year = {2025}
}