Orthorhombic distortions may reconcile all the experimental data on YBCO

TL;DR

This paper proposes that orthorhombic distortions in YBCO can reconcile conflicting experimental data by suggesting a significant orthorhombicity that mixes s- and d-wave pairing, especially if the Fermi surface is square-shaped.

Contribution

It introduces a hypothesis that orthorhombic distortions are substantial enough to explain diverse experimental results in YBCO, unifying the data through a mixed pairing symmetry.

Findings

Orthorhombicity can explain conflicting experimental data.

A square-shaped Fermi surface supports the proposed reconciliation.

Mixing of s- and d-wave pairing is plausible in YBCO.

Abstract

A lot of controversy appeared recently in measurements of different properties of High-$T_c$-superconductor YBCO. A part of data supports d-wave hypothesis whereas other one contradicts it. We suggest to reconcile visibly controversial experimental data by an assumption that orthorombicity is not small for electronic properties of YBCO, and naturally mixes s- and d-pairing. We examine available experiments to find a proportion of such a mixture. We find in particular that the reconcilation is plausible if the Fermi-surface in YBCO is square-shaped.