Spin-triplet f-wave pairing due to three-site cyclic-exchange ferromagnetic interactions

TL;DR

This paper investigates how three-site cyclic-exchange ferromagnetic interactions can induce spin-triplet f-wave pairing in a two-dimensional triangular-lattice Hubbard model, suggesting a possible mechanism for unconventional superconductivity.

Contribution

It proposes a novel mechanism for f-wave spin-triplet pairing driven by cyclic-exchange ferromagnetic interactions in triangular-lattice systems.

Findings

Identification of a pairing mechanism via cyclic-exchange interactions.

Application to real materials like Bechgaard salts and Sr2RuO4.

Use of density-matrix renormalization group method for analysis.

Abstract

Ferromagnetiam and superconductivity in a two-dimensional triangular-lattice Hubbard model are studied using the density-matrix renormalization group method. We propose a mechanism of the {\it f}-wave spin-triplet pairing derived from the three-site cyclic-exchange ferromagnetic interactions. We point out that a triangular network of hopping integrals, which is required for the three-site cyclic hopping processes, is contained in the (possibly) spin-triplet superconducting systems, such as Bechgaard salts (TMTSF)$_2$X, cobalt oxide Na$_{0.35}$CoO$_2$$\cdot$1.3H$_2$O, and layered perovskite Sr$_2$RuO$_4$.