Scaling properties of induced density of chiral and nonchiral Dirac fermions in magnetic fields

Abstract

We find that a repulsive potential of graphene in the presence of a magnetic field has bound states that are peaked inside the barrier with tails extending over $\ensuremath{\ell}(N+1)$, where $\ensuremath{\ell}$ and $N$ are the magnetic length and Landau level index. We have investigated how these bound states affect scaling properties of the induced density of filled Landau levels of massless Dirac fermions. For chiral fermions, we find, in strong coupling regime, that the density inside the repulsive potential can be greater than the value in the absence of the potential, while in the weak coupling regime, we find negative induced density. Similar results also hold for nonchiral fermions. As one moves from weak to strong coupling regimes, the effective coupling constant between the potential and electrons becomes more repulsive, and then it changes sign and becomes attractive. Different power laws of induced density are found for chiral and nonchiral fermions.