Hall number, specific heat and superfluid density of overdoped high-Tc cuprates

TL;DR

This paper explains various unexpected properties of heavily overdoped high-Tc cuprates by combining pair-breaking scattering with Fermi surface reconstruction, challenging previous pseudogap theories.

Contribution

It introduces a model integrating pair-breaking scattering with Fermi surface reconstruction to explain anomalous thermodynamic and Hall effect observations in overdoped cuprates.

Findings

Pair-breaking increases with doping, affecting the pseudogap and Fermi surface.

Reconstruction points and thermodynamic peaks diverge due to pair-breaking.

The model accounts for the high-doping Hall number transition.

Abstract

Despite often being dismissively described as exhibiting conventional Fermi-liquid-like behaviour, heavily overdoped high-Tc cuprates sport several unexpected features. Thermodynamic properties expected to be roughly constant with doping decrease towards zero, signalling that a growing fraction of carriers remain in the normal state below Tc. Near Tc, the superconducting energy gap fills in with temperature, contrary to the expectations of BCS theory. Most recently a transition in the Hall number of some cuprates was found to extend to a very high doping (x~0.27), far beyond the pseudogap critical point identified by a peak in thermodynamic properties (x=0.19). This presents a challenge to the view that the pseudogap is a consequence of Fermi surface reconstruction. In this paper we present a consistent explanation for all these observations by combining pair-breaking scattering with a Fermi surface reconstruction model for the pseudogap. Notably, an increase in pair-breaking with doping leads to a separation of the points where reconstruction begins and the thermodynamic properties peak. This result highlights pair-breaking as an essential ingredient in the electronic recipe for heavily overdoped cuprate superconductors.