Landau Quantization in Twisted Bilayer Graphenes: the Dirac Comb

TL;DR

This paper investigates how twisting bilayer graphene affects its electronic Landau levels, revealing distinct spectral features for different stacking types and proposing experimental methods to probe weak interlayer couplings.

Contribution

It introduces a detailed analysis of Landau quantization in twisted bilayer graphene, highlighting differences between sublattice exchange parity families and their spectral modulations.

Findings

Distinct Landau spectra for two bilayer families

Spectral modulations reveal interlayer coupling effects

Proposes experimental probes for weak coherence splitting

Abstract

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 a powerful experimental probe of the magnitude of a weak coherence splitting in a bilayer and its low energy mass structure.