Non-divergent Fermi velocity for interacting graphene at the Dirac point

TL;DR

This paper uses non-perturbative bosonization techniques to show that the Fermi velocity in interacting graphene remains finite at the Dirac point, challenging previous perturbative predictions of divergence.

Contribution

It introduces a bosonized, non-perturbative approach to analyze electron interactions in graphene, demonstrating a finite Fermi velocity at charge neutrality.

Findings

Fermi velocity remains finite at the Dirac point

Experimental observations are better explained by an anomalous dimension

Provides a bosonized solution for (2+1)D Weyl fermions

Abstract

Recent experiments reveal a significant increase in the graphene Fermi velocity close to charge neutrality. This has widely been interpreted as a confirmation of the logarithmic divergence of the graphene Fermi velocity predicted by a perturbative approach. In this work, we reconsider this problem using functional bosonization techniques calculating the effects of electron interactions on the density of states non-perturbatively. We find that the renormalized velocity is {\it finite} and independent of the high energy cut-off, and we argue that the experimental observations are better understood in terms of an anomalous dimension. Our results also represent a bosonized solution for interacting Weyl fermions in (2+1) dimensions at half-filing.