Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 34: Transport: Graphene (jointly with CPP, DS, DY, HL, MA, O)

TT 34.7: Vortrag

Dienstag, 17. März 2015, 11:15–11:30, A 053

Density of states of graphene with vacancies — •Soumya Bera — MPI-PKS, Dresden

We numerically calculate the density of states (DOS) of graphene in the presence of compensated vacancy disorder. The model belongs to the BDI class of Atland-Zirnbauer symmetry classification of disordered metals, where the non-linear Sigma model predicts a Gade-type singularity in the DOS ρ(E) ∼ E⁻¹ exp(−|log(E)|^−1/2). We show that in the pre-asymptotic regime this is indeed true, however, at even lower energies the Gade-type behavior gives away to a stronger singularity of the form ρ(E) ∼ E⁻¹ |log(E)|^−x with 2> x ≥ 1 in agreement with recent analytical work (Ostrovsky et al., PRL 113, 186803). We conclude that the generic Sigma model of the BDI class does not apply for strong (unitary) scatterers; the nature of disorder is of important to determine the low energy behaviour of disordered graphene.

[1] PRL 113, 186802 (2014).