Resilient Fermi liquid and strength of correlations near an antiferromagnetic quantum critical point

TL;DR

This paper uses a two-particle self-consistent theory to analyze the stability of Fermi liquids near an antiferromagnetic quantum critical point in electron-doped cuprates, revealing how quasiparticle properties evolve and proposing a new correlation gauge.

Contribution

It demonstrates the stability of the Fermi liquid in the antinodal region near the QCP and introduces a measurable dimensionless number to gauge correlation strength.

Findings

Fermi liquid remains stable over a broad angle range near the QCP

Quasiparticle weight Z and effective mass m* change abruptly near hot spots

Proposes an experimentally accessible correlation strength gauge

Abstract

Near the antiferromagnetic quantum critical point (QCP) of electron-doped cuprate superconductors, angle-resolved photoemission experiments detect hot spots where the Fermi surface disappears. Here we demonstrate, using the two-particle self-consistent theory, that in the antinodal region the Fermi liquid remains stable for a broad range of angles on the Fermi surface and for all dopings near the QCP. We show how the quasiparticle weight Z and effective mass m* change and then abruptly become meaningless as the hot spots are approached. We propose a dimensionless number, easily accessible in ARPES experiments, that can be used to gauge the strength of correlations.