Regensburg 2016 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 51: Transport: Graphene (Joint session of DS, DY, HL, MA, O and TT, organized by TT)
HL 51.2: Talk
Wednesday, March 9, 2016, 10:00–10:15, H22
Double-logarithmic velocity renormalization at the Dirac points of graphene — •Peter Kopietz, Anand Sharma, and Carsten Bauer — Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue Str. 1, 60438 Frankfurt
Using a functional renormalization group approach with partial bosonization in the forward scattering channel we reconsider the effect of long-range Coulomb interactions on the quasi-particle velocity vk close to the Dirac points of graphene. In contrast to calculations based on perturbation theory and field theoretical renormalization group methods, we find that vk is proportional to ln[ κk / k ] where k is the deviation of the quasiparticle momentum from the Dirac points and the cutoff scale κk vanishes logarithmically for small k. We show that this double-logarithmic singularity is compatible with experiments and with the known three-loop expansion of vk which contains terms of order lnk and ln2 k.