Superconducting Resonance and paring symmetry in electron-doped cuprates

TL;DR

This paper investigates magnetic excitations and resonance phenomena in electron-doped cuprates, linking resonance energy to superconducting gap and pairing symmetry, and proposes a new experimental method to determine pairing symmetry.

Contribution

It demonstrates the universality of the resonance energy scaling with the superconducting gap and relates it to pairing symmetry, providing insights into the nature of superconductivity in electron-doped cuprates.

Findings

Resonance energy scales linearly with superconducting gap, with E_res/2Δ ≈ 0.6.

A lower-energy peak is predicted when the hole pocket appears.

Monotonic d-wave pairing symmetry best matches experimental data.

Abstract

The magnetic excitations in the superconducting electron-doped cuprates are studied in the framework of spin-density-wave description. The superconducting resonance is a natural product of the superconductivity due to the opening of d-wave gap. Its resonance energy exhibits well linear scaling with superconducting gap as $E_{res}/2\Delta\sim 0.6$, quantitatively consisting with the experimental discovery. This ratio is insensitive to the selected parameters, manifesting its universality. Another lower-energy peak below resonance energy is predicted when the hole pocket emerges due to suppression of spin-density wave. We further verify that the ratio of linear scales is intimately related to the pairing symmetry. Distinct ratio can be found with respective pairing symmetry. In comparison with the inelastic neutron scattering data, the monotonic d-wave superconductivity is the most likely candidate in the electron-doped cuprates. Furthermore, we proposed a new method to check the pairing symmetry by the inelastic neutron scattering measurements.