Landau quantization in twisted bilayer graphene: The Dirac comb

We study the Landau quantization of the electronic spectrum for graphene bilayers that are rotationally faulted to produce periodic superlattices. Commensurate twisted bilayers exist in two families distinguished by their sublattice exchange parity. We show that these two families exhibit distinct Landau quantized spectra distinguished both by the interlayer coupling of their zero modes and by an amplitude modulation of their spectra at energies above their low-energy interlayer coherence scales. These modulations can provide an experimental probe of the magnitude of a weak coherence splitting in a bilayer and its low-energy mass structure.