Bernal-stacked multilayer graphene is a versatile platform to explore quantum transport phenomena and interaction physics due to its exceptional tunability via electrostatic gating. For instance, upon applying a perpendicular electric field, its band structure exhibits several off-center Dirac points (so-called Dirac gullies) in each valley. Here, the formation of Dirac gullies and the interaction-induced breakdown of gully coherence is explored via magnetotransport measurements in high-quality Bernal-stacked (ABA) trilayer graphene. At zero magnetic field, multiple Lifshitz transitions indicating the formation of Dirac gullies are identified. In the quantum Hall regime, the emergence of Dirac gullies is evident as an increase in Landau level degeneracy. When tuning both electric and magnetic fields, electron–electron interactions can be controllably enhanced until, beyond critical electric and magnetic fields, the gully degeneracy is eventually lifted. The arising correlated ground state is consistent with a previously predicted nematic phase that spontaneously breaks the rotational gully symmetry.
We acknowledge funding from the Center for Nanoscience (CeNS) and by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy-EXC-2111-390814868 (MCQST). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant Number PMXP0112101001) and JSPS KAKENHI (Grant Numbers 19H05790 and JP20H00354).
Winterer F, Seiler AM, Ghazaryan A, et al. Spontaneous gully-polarized quantum hall states in ABA trilayer graphene. Nano Letters. 2022;22(8):3317-3322. doi:10.1021/acs.nanolett.2c00435
Winterer, F., Seiler, A. M., Ghazaryan, A., Geisenhof, F. R., Watanabe, K., Taniguchi, T., … Weitz, R. T. (2022). Spontaneous gully-polarized quantum hall states in ABA trilayer graphene. Nano Letters. American Chemical Society. https://doi.org/10.1021/acs.nanolett.2c00435
Winterer, Felix, Anna M. Seiler, Areg Ghazaryan, Fabian R. Geisenhof, Kenji Watanabe, Takashi Taniguchi, Maksym Serbyn, and R. Thomas Weitz. “Spontaneous Gully-Polarized Quantum Hall States in ABA Trilayer Graphene.” Nano Letters. American Chemical Society, 2022. https://doi.org/10.1021/acs.nanolett.2c00435.
F. Winterer et al., “Spontaneous gully-polarized quantum hall states in ABA trilayer graphene,” Nano Letters, vol. 22, no. 8. American Chemical Society, pp. 3317–3322, 2022.
Winterer F, Seiler AM, Ghazaryan A, Geisenhof FR, Watanabe K, Taniguchi T, Serbyn M, Weitz RT. 2022. Spontaneous gully-polarized quantum hall states in ABA trilayer graphene. Nano Letters. 22(8), 3317–3322.
Winterer, Felix, et al. “Spontaneous Gully-Polarized Quantum Hall States in ABA Trilayer Graphene.” Nano Letters, vol. 22, no. 8, American Chemical Society, 2022, pp. 3317–22, doi:10.1021/acs.nanolett.2c00435.