Narrow depression in the density of states at the Dirac point in disordered graphene

Abstract

The electronic properties of non-interacting particles moving on a two-dimensional bricklayer lattice are investigated numerically. In particular, the influence of disorder in form of a spatially varying random magnetic flux is studied. In addition, a strong perpendicular constant magnetic field $B$ is considered. The density of states $\rho (E)$ goes to zero for $E\to 0$ as in the ordered system, but with a much steeper slope. This happens for both cases: at the Dirac point for B=0 and at the center of the central Landau band for finite $B$. Close to the Dirac point, the dependence of $\rho (E)$ on the system size, on the disorder strength, and on the constant magnetic flux density is analyzed and fitted to an analytical expression proposed previously in connection with the thermal quantum Hall effect. Additional short-range on-site disorder completely replenishes the indentation in the density of states at the Dirac point.

revised version, 7 pages, 10 figures

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Cited by in corpus (6)

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• Correlated random hopping disorder in graphene at high magnetic fields: Landau level broadening and localization properties
• Disordered two-dimensional electron systems with chiral symmetry
• Logarithmic scaling of Lyapunov exponents in disordered chiral two-dimensional lattices
• Scaling at chiral quantum critical points in two dimensions
• Shape of the zeroth Landau level in graphene with non-diagonal disorder