Horizontal line nodes in superconducting Sr2RuO4

TL;DR

This paper investigates triplet pairing in Sr2RuO4, proposing models with horizontal line nodes influenced by interlayer coupling, and compares their predictions with experimental data on heat capacity and penetration depth.

Contribution

It introduces two models of triplet pairing with different nodal structures in Sr2RuO4 based on interlayer coupling effects.

Findings

Both models fit heat capacity and penetration depth data.

The model with nodes only on alpha and beta sheets aligns more closely with specific heat measurements.

Horizontal line nodes are consistent with experimental observations.

Abstract

We analyze the possibilities of triplet pairing in Sr2RuO4 based upon an idea of interlayer coupling. We have considered two models differing by the effective interactions. In one model the quasi-particle spectra have horizontal line nodes on all three Fermi surface sheets, while in the other the spectra have line or point nodes on the alpha and beta sheets and no nodes on the gamma sheet. Both models reproduce the experimental heat capacity and penetration depth results, but the calculated specific heat is sightly closer to experiment in the second solution with nodes only on the alpha and beta sheets.