Realization of odd-frequency p-wave spin-singlet superconductivity coexisting with antiferromagnetic order near quantum critical point

TL;DR

This paper investigates the theoretical possibility of odd-frequency p-wave spin-singlet superconductivity coexisting with antiferromagnetic order near a quantum critical point, providing insights into anomalous experimental behaviors.

Contribution

It demonstrates that odd-frequency p-wave spin-singlet superconductivity can prevail over d-wave near the antiferromagnetic quantum critical point, offering a new perspective on coexistence with antiferromagnetism.

Findings

p-wave spin-singlet superconductivity is favored near QCP

No gap in quasiparticle spectrum due to odd frequency

Explains anomalous NQR relaxation in Ce-based compounds

Abstract

A possibility of the realization of the p-wave spin-singlet superconductivity ($p$SS), whose gap function is odd both in momentum and in frequency, is investigated by solving the gap equation with the phenomenological interaction mediated by the antiferromagnetic spin fluctuation. The $p$SS is realized prevailing over the d-wave singlet superconductivity ($d$SS) in the vicinity of antiferromagnetic quantum critical pint (QCP) both on the paramagnetic and on the antiferromagnetic sides. Off the QCP in the paramagnetic phase, however, the $d$SS with line-nodes is realized as \textit{conventional} anisotropic superconductivity. For the present $p$SS state, there is no gap in the quasiparticle spectrum everywhere on the Fermi surface due to its odd frequency. These features can give a qualitative understanding of the anomalous behaviors of NQR relaxation rate on CeCu$_2$Si$_2$ or CeRhIn$_5$ where the antiferromagnetism and superconductivity coexist on a microscopic level.