Superconductivity by Kinetic Energy Saving?

TL;DR

This paper examines the microscopic mechanisms of superconductivity, comparing BCS and non-Fermi liquid scenarios, and evaluates their predictions against experimental data on kinetic energy and spectral weight.

Contribution

It provides a quantitative comparison of BCS and non-Fermi liquid models for superconductivity, highlighting discrepancies with experimental observations.

Findings

BCS predicts the wrong sign for the spectral weight kink at Tc

Model calculations align with specific heat data

Differences between theoretical predictions and experimental spectral weight behavior

Abstract

A brief introduction is given in the generic microscopic framework of superconductivity. The consequences for the temperature dependence of the kinetic energy, and the correlation energy are discussed for two cases: The BCS scenario and the non-Fermi liquid scenario. A quantitative comparison is made between the BCS-prediction for d-wave pairing in a band with nearest neighbor and next-nearest neighbor hoppping and the experimental specific heat and the optical intraband spectral weight along the plane. We show that the BCS-prediction produces the wrong sign for the kink at Tc of the intraband spectral weight, even though the model calculation agrees well with the specific heat.