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arXiv · 1603.01188

Multilogarithmic velocity renormalization in graphene

Anand Sharma·Peter Kopietz
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Abstract

We reexamine the effect of long-range Coulomb interactions on the quasiparticle velocity in graphene. Using a nonperturbative functional renormalization group approach with partial bosonization in the forward scattering channel and momentum transfer cutoff scheme, we calculate the quasiparticle velocity, $v (k)$, and the quasiparticle residue, $Z$, with frequency-dependent polarization. One of our most striking results is that $v ( k ) \propto \ln [ C_k (α) / k ]$ where the momentum- and interaction-dependent cutoff scale $C_k (α) $ vanishes logarithmically for $k \rightarrow 0$. Here $k$ is measured with respect to one of the charge neutrality (Dirac) points and $α=2.2$ is the strength of dimensionless bare interaction. Moreover, we also demonstrate that the so-obtained multilogarithmic singularity is reconcilable with the perturbative expansion of $v (k)$ in powers of the bare interaction.

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Anand Sharma, Peter Kopietz. 2016-06-20. Multilogarithmic velocity renormalization in graphene. https://doi.org/10.1103/physrevb.93.235425

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