Identification of the bulk pairing symmetry in high-temperature superconductors: Evidence for an extended s-wave with eight line nodes

TL;DR

This paper identifies the intrinsic bulk pairing symmetry in high-temperature cuprate superconductors, providing evidence for an extended s-wave with eight line nodes in hole-doped and anisotropic s-wave in electron-doped variants, reconciling various experimental results.

Contribution

It offers a comprehensive analysis of multiple experimental data to determine the bulk pairing symmetry, proposing an extended s-wave with eight line nodes as the dominant symmetry in hole-doped cuprates.

Findings

Bulk pairing symmetry in hole-doped cuprates is extended s-wave with eight line nodes.

Electron-doped cuprates exhibit anisotropic s-wave pairing symmetry.

The proposed symmetries reconcile surface-sensitive and bulk-sensitive experimental results.

Abstract

we identify the intrinsic bulk pairing symmetry for both electron and hole-doped cuprates from the existing bulk- and nearly bulk-sensitive experimental results such as magnetic penetration depth, Raman scattering, single-particle tunneling, Andreev reflection, nonlinear Meissner effect, neutron scattering, thermal conductivity, specific heat, and angle-resolved photoemission spectroscopy. These experiments consistently show that the dominant bulk pairing symmetry in hole-doped cuprates is of extended s-wave with eight line nodes, and of anisotropic s-wave in electron-doped cuprates. The proposed pairing symmetries do not contradict some surface- and phase-sensitive experiments which show a predominant d-wave pairing symmetry at the degraded surfaces. We also quantitatively explain the phase-sensitive experiments along the c-axis for both Bi_{2}Sr_{2}CaCu_{2}O_{8+y} and YBa_{2}Cu_{3}O_{7-y}.