Saddle-point van Hove singularity and the phase diagram of high-Tc cuprates

TL;DR

This paper investigates the phase diagram of high-Tc cuprates, revealing a universal van Hove singularity and showing that the pairing interaction diminishes with doping, favoring magnetic over phonon-based mechanisms.

Contribution

It demonstrates the role of a van Hove singularity in the phase behavior and provides evidence against phonon-mediated pairing in high-Tc cuprates.

Findings

Van Hove singularity is universal in overdoped cuprates.

Pairing interaction declines rapidly with doping.

Magnetic interactions are more consistent with observed data.

Abstract

We examine the generic phase behavior of high-Tc cuprate superconductors in terms a universal van Hove singularity in the strongly overdoped region. Using a rigid ARPES-derived dispersion we solve the BCS gap equation and show that the pairing interaction or pairing energy cutoff must be a rapidly declining function of doping. This result is prejudicial to a phonon-based pairing interaction and more consistent with a magnetic or magnetically enhanced interaction.