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arXiv · 1310.8578

Dirac edges of fractal magnetic minibands in graphene with hexagonal moire superlattices

Xi Chen·J. R. Wallbank·A. A. Patel·M. Mucha-Kruczynski·E. McCann·V. I. Fal'ko
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Abstract

We find a systematic reappearance of massive Dirac features at the edges of consecutive minibands formed at magnetic fields B_{p/q}= pϕ_0/(qS) providing rational magnetic flux through a unit cell of the moire superlattice created by a hexagonal substrate for electrons in graphene. The Dirac-type features in the minibands at B=B_{p/q} determine a hierarchy of gaps in the surrounding fractal spectrum, and show that these minibands have topological insulator properties. Using the additional $q$-fold degeneracy of magnetic minibands at B_{p/q}, we trace the hierarchy of the gaps to their manifestation in the form of incompressible states upon variation of the carrier density and magnetic field.

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Xi Chen, J. R. Wallbank, A. A. Patel, M. Mucha-Kruczynski, E. McCann, V. I. Fal'ko. 2014-01-13. Dirac edges of fractal magnetic minibands in graphene with hexagonal moire superlattices. https://doi.org/10.1103/physrevb.89.075401

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