Even-parity spin-triplet paired states by combined effect of Hund’s rule and correlations in two-band Hubbard model: a brief overview

Abstract

Universal aspects of the Hund’s rule induced spin-triplet pairing are analysed within the two-band Hubbard model on a square lattice. According to our calculations, this pairing mechanism in conjunction with the correlation effect can result in stability of the paired phase in the so-called purely repulsive interactions regime, in which there is no effectively attractive interaction. Furthermore, even though all of the interaction terms are of intrasite character, the pairing contains both intra- and inter-site components. In effect, the gap parameter has a mixture of s-wave and extended s-wave symmetries. The calculations have been carried out with the use of the Statistically Consistent Gutzwiller Approximation developed by us in recent years.

Keywords:

• spin-triplet pairing
• superconductivity
• Hubbard model
• Gutzwiller approximation

Acknowledgements

Discussions with Józef Spałek and Jörg Bünemann are gratefully acknowledged. This work has been supported by the Foundation for Polish Science (FNP) within the project TEAM.