A novel class of singlet superconductors

TL;DR

This paper introduces a new class of singlet superconductors characterized by an odd gap function in both momentum and frequency, discussing their physical properties and potential for electron-phonon induced pairing.

Contribution

It proposes a novel class of superconductors with an odd gap function, expanding the understanding of pairing mechanisms and physical properties.

Findings

Electron-phonon interaction can produce this pairing

No gap in quasiparticle spectrum in many cases

Exhibits Meissner effect

Abstract

A new class of singlet superconductors with a gap function $\Delta(\bk, \omega_n)$ which is {\it odd} in both momentum and Matsubara frequency is considered. Some of the physical properties of this superconductivity are discussed and it is argued that: i) the electron-phonon interaction can produce this kind of pairing, ii) in many cases there is no gap in the quasiparticle spectrum, iii) these superconductors will exhibit a Meissner effect.