Specific heat across the superconducting dome in the cuprates

TL;DR

This paper models the specific heat of cuprate superconductors across their phase diagram, incorporating pseudogap effects and quantum criticality, aligning well with experimental data.

Contribution

It introduces a comprehensive theoretical framework that captures the doping-dependent specific heat behavior, including pseudogap effects and a quantum critical point.

Findings

Rapid increase in the slope of linear T specific heat above optimal doping

Agreement with experimental data on Bi-based cuprates under magnetic fields

Identification of a quantum critical point below optimal doping

Abstract

The specific heat of the superconducting cuprates is calculated over the entire phase diagram. A d-wave BCS approach based on the large Fermi surface of Fermi liquid and band structure theory provides a good description of the overdoped region. At underdoping it is essential to include the emergence of a second energy scale, the pseudogap and its associated Gutzwiller factor, which accounts for a reduction in the coherent piece of the electronic Green's function due to increased correlations as the Mott insulating state is approached. In agreement with experiment, we find that the slope of the linear in T dependence of the low temperature specific heat rapidly increases above optimum doping while it is nearly constant below optimum. Our theoretical calculations also agree with recent data on Bi$_2$Sr$_{2-\rm x}$La$_{\rm x}$CuO$_{6+\delta}$ for which the normal state is accessed through the application of a large magnetic field. A quantum critical point is located at a doping slightly below optimum.