Fermion dispersion renormalization in a two-dimensional semi-Dirac semimetal

TL;DR

This paper investigates how long-range Coulomb interactions significantly alter the fermion dispersion in a two-dimensional semi-Dirac semimetal, transforming it from mixed linear-quadratic to fully linear in both directions.

Contribution

It provides a non-perturbative, self-consistent analysis of Coulomb effects on semi-Dirac fermions, revealing a transition to linear dispersion in both directions.

Findings

Fermion dispersion becomes linear in both directions due to Coulomb interactions.

The study employs Dyson-Schwinger equations for a non-perturbative approach.

Results differ from previous models that did not account for strong correlation effects.

Abstract

We present a non-perturbative study of the quantum many-body effects caused by the long-range Coulomb interaction in a two-dimensional semi-Dirac semimetal. This kind of semimetal may be realized in deformed graphene and a class of other realistic materials. In the non-interacting limit, the dispersion of semi-Dirac fermion is linear in one direction and quadratic in the other direction. When the impact of Coulomb interaction is taken into account, such a dispersion can be significantly modified. To reveal the correlation effects, we first obtain the exact self-consistent Dyson-Schwinger equation of the full fermion propagator and then extract the momentum dependence of the renormalized fermion dispersion from the numerical solutions. Our results show that the fermion dispersion becomes linear in two directions. These results are compared to previous theoretical works on semi-Dirac semimetals.