Strong- versus Weak-Coupling Paradigms for Cuprate Superconductivity

TL;DR

This study measures resistivity in various cuprate thin films and compares the results with both strong and weak coupling theories, finding agreement with both and discussing how to differentiate them further.

Contribution

It provides experimental resistivity data across different cuprates and evaluates their consistency with competing strong and weak coupling theoretical models.

Findings

Results agree with both strong and weak coupling paradigms

Resistivity slope analysis near Tc and T*

Discussion on missing calculations to distinguish theories

Abstract

Absolute resistivity measurements as a function of temperature from optimally doped YBa_2Cu_3O_(7), La_(2-x)Sr_xCuO_4, Bi_2Sr_2CaCu_2O_(8-x), and (Ca_0.1La_0.9)(Ba_1.65La_0.35)Cu_3O_y thin films are reported. Special attention is given to the measurement geometrical factors and the resistivity slope between Tc and T^{*}. The results are compared with a strong coupling theory for the resistivity derivative near T_c, which is based on hard core bosons (HCB), and with several weak coupling theories, which are BCS based. Surprisingly, our results agree with both paradigms. The implications of these findings and the missing calculations needed to distinguish between the two paradigms are discussed.