Zero-energy modes and valley asymmetry in the Hofstadter spectrum of bilayer graphene van der Waals heterostructures with hBN

Chen, Xi and Wallbank, John and Mucha-Kruczynski, Marcin and McCann, Edward and Falko, Vladimir (2016) Zero-energy modes and valley asymmetry in the Hofstadter spectrum of bilayer graphene van der Waals heterostructures with hBN. Physical review B, 94 (4). ISSN 1098-0121

[img]
Preview
PDF (Hofstadter_spectrum_of_BLG_author-accepted)
Hofstadter_spectrum_of_BLG_author_accepted.pdf - Accepted Version
Available under License Creative Commons Attribution-NonCommercial.

Download (2MB)

Abstract

We investigate the magnetic minibands of a heterostructure consisting of bilayer graphene (BLG) and hexagonal boron nitride (hBN) by numerically diagonalizing a two-band Hamiltonian that describes electrons in BLG in the presence of a moiré potential. Due to inversion-symmetry breaking characteristic for the moiré potential, the valley symmetry of the spectrum is broken, but despite this, the zero-energy Landau level in BLG survives, albeit with reduced degeneracy. In addition, we derive effective models for the low-energy features in the magnetic minibands and demonstrate the appearance of secondary Dirac points in the valence band, which we confirm by numerical simulations. Then, we analyze how single-particle gaps in the fractal energy spectrum produce a sequence of incompressible states observable under a variation of carrier density and magnetic field.

Item Type: Journal Article
Journal or Publication Title: Physical review B
Departments: Faculty of Science and Technology > Physics
ID Code: 80626
Deposited By: ep_importer_pure
Deposited On: 31 Aug 2016 15:44
Refereed?: Yes
Published?: Published
Last Modified: 21 Oct 2019 00:47
URI: https://eprints.lancs.ac.uk/id/eprint/80626

Actions (login required)

View Item View Item