We find a systematic reappearance of massive Dirac features at the edges of consecutive minibands formed at magnetic fields Bp/q=pqφ0/S providing rational magnetic flux through a unit cell of the moiré superlattice created by a hexagonal substrate for electrons in graphene. The Dirac-type features in the minibands at B=Bp/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 Bp/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.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 5 Feb 2014|
Research Beacons, Institutes and Platforms
- National Graphene Institute