Competition between singlet and triplet superconductivity

TL;DR

This paper investigates the competition between singlet and triplet superconductivity within an extended Hubbard model, highlighting the conditions under which triplet pairing can emerge despite strong correlations favoring singlet pairing.

Contribution

It demonstrates that triplet superconductivity is unlikely in the standard Hubbard model and requires additional interactions like electron-phonon coupling or ferromagnetic exchange.

Findings

Strong correlations favor singlet over triplet superconductivity.

Triplet pairing likely induced by electron-phonon or ferromagnetic interactions.

Magnetism can be detrimental to superconductivity under certain conditions.

Abstract

The competition between singlet and triplet superconductivity is examined in consideration of correlations on an extended Hubbard model. It is shown that the triplet superconductivity may not be included in the common Hubbard model since the strong correlation favors the singlet superconductivity, and thus the triplet superconductivity should be induced by the electron-phonon interaction and the ferromagnetic exchange interaction. We also present a superconducting qualification with which magnetism is unbeneficial to superconductivity.