2008/10/21 by Oskar Vafek, Vafek, Oskar
Materials Science · Physics and Astronomy · #Carbon Nanotubes in Composites #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #cond-mat.dis-nn
paper · pdf · doi:10.48550/arxiv.0810.3697
4+ pages, 5 figures
arxiv created 2008/10/21 · openalex publication_date 2008/10/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Frequency dependent conductivity of Coulomb interacting massless Dirac fermions coupled to random scalar and random vector potentials is found as a function of frequency in the regime controlled by a line of fixed points. Such model provides a low energy description of a weakly rippled suspended graphene. The main finding is that at the neutrality point the a.c. conductivity is not frequency independent and may either increase or decrease with decreasing frequency, depending on the values of the disorder variances Δϕ, ΔA and the Coulomb coupling α=e2/(\eps vF). The low frequency behavior is characterized by the values of two dimensionless parameters γ=Δϕ/α2 and ΔA which are RG invariants, and for small values of which the electron-hole "puddles" are effectively screened making the results asymptotically exact.