Renormalization Group Approach to the Normal State of Copper-Oxide Superconductors

TL;DR

This paper uses renormalization group techniques to analyze how van Hove singularities affect the normal state of copper-oxide superconductors, revealing deviations from Fermi liquid behavior and explaining experimental observations.

Contribution

It introduces a renormalization group framework to understand the impact of van Hove singularities on electronic properties in copper-oxide superconductors, highlighting an unstable fixed point.

Findings

Deviations from Fermi liquid behavior due to van Hove singularities

Reduction in band dispersion near the Fermi level

Pinning of the Fermi level at the singularity

Abstract

We study by means of renormalization group techniques the effect that on the two-dimensional electron liquid may have the van Hove singularities observed experimentally in the copper-oxide superconductors. We find significant deviations from Fermi liquid behavior, that lead to the appearance of an unstable fixed point in the renormalization group flow of the effective coupling constant. Besides the attenuation of electron quasiparticles already known on phenomenological grounds, our approach is able to explain the reduction in the dispersion of the band as well as the pinning of the Fermi level near the singularity, as observed in the photoemission experiments.