Theoretical analysis of the density of states of graphene at high magnetic fields using Haldane pseudopotentials

We study the density of states in graphene at a high magnetic field, when the physics is dominated by strong correlations between electrons. In particular, we use the method of Haldane pseudopotentials to focus on almost-empty or almost-filled Landau levels. We find that, besides the usual Landau level peaks, additional peaks (“sashes”) appear in the spectrum. The energies of these peaks are determined by the strength of Haldane's pseudopotentials, but as opposed to the usual two-dimensional gas, where there is a one-to-one correspondence between a Haldane pseudopotential and a peak in the spectrum, the energy of each peak is determined in general by a combination of more than one pseudopotential value. An eventual measure of these peak in the density-of-states spectrum of graphene would allow one to determine the value of the pseudopotentials in graphene and, thus, test the strength of the interactions in this system.