Bulk Evidence for s-Wave Pairing Symmetry in the n-Type Infinite-Layer Cuprate $Sr_{0.9}La_{0.1}CuO_{2}$

TL;DR

This study provides bulk thermodynamic evidence supporting s-wave pairing symmetry in the electron-doped cuprate Sr0.9La0.1CuO2, contrasting with the d-wave symmetry observed in hole-doped cuprates.

Contribution

It offers the first bulk thermodynamic evidence for s-wave pairing in an n-type infinite-layer cuprate, complementing previous tunneling studies.

Findings

Quasiparticle DOS consistent with s-wave pairing symmetry.

Vortex core contributions dominate the electronic DOS.

Contrasts with d-wave symmetry in p-type cuprates.

Abstract

Low temperature specific heat of the electron-doped (n-type) infinite-layer cuprate $Sr_{0.9}La_{0.1}CuO_{2}$ has been measured. The quasiparticle density of states (DOS) in the mixed state is found to be consistent with the feature of the s-wave pairing symmetry, agreeing very well with the earlier tunnelling measurement, but being contrary to the d-wave symmetry well confirmed for the hole-doped (p-type) cuprates. Our results indicate that the electronic DOS are mainly contributed by the vortex cores in the present sample being contrast to the p-type cuprates in which the vortex cores are abnormal and contribute very limited low energy DOS as evidenced by many means.