Multiorbital and hybridization effects in the quasiparticle interference of triplet superconductor Sr2RuO4

TL;DR

This paper investigates the multiorbital effects and hybridization in Sr2RuO4's quasiparticle interference patterns, proposing STM-QPI as a tool to better understand its unconventional chiral p-wave superconducting gap structure.

Contribution

It introduces a three-band chiral gap model with analytical QPI expressions, linking quasiparticle interference features to the superconducting gap structure in Sr2RuO4.

Findings

QPI spectra show characteristic bias-dependent changes.

The model provides a way to quantitatively determine the chiral gap structure.

Analytical expressions enable detailed comparison with experimental data.

Abstract

The tetragonal compound Sr2RuO4 exhibits a chiral p-wave superconducting (SC) state of its three t2g-type conduction bands. The characteristics of unconventional gap structure are known from experiment, in particular field-angle resolved specific heat measurements and from microscopic theories. A rotated extremal structure on the main active SC band with respect to the nodal gaps on the passive bands was concluded. We propose that this gap structure can be further specified by applying the STM- quasiparticle interference (QPI) method. We calculate the QPI spectrum within a three band and chiral three gap model and give closed analytical expressions. We show that as function of bias voltage the chiral three gap model will lead to characteristic changes in QPI that may be identified and may be used for more quantitative gap determination of the chiral gap structure.