Spin-triplet pairing instability of the spinon Fermi surface in a U(1) spin liquid

TL;DR

This paper investigates the potential for spin-triplet pairing instabilities in a U(1) spin liquid with a spinon Fermi surface, motivated by experimental observations in organic compounds, revealing possible unconventional pairing mechanisms.

Contribution

It identifies conditions under which spin-triplet pairing instabilities can occur in a U(1) spin liquid, extending understanding of pairing phenomena in spinon Fermi surfaces.

Findings

Pairing instability occurs in odd-angular-momentum/spin-triplet channels.

Singular interactions at twice the Fermi momentum drive the instability.

Implications for experimental detection of unconventional superconductivity.

Abstract

Recent experiments on the organic compound \kappa-(ET)_2Cu_2(CN)_3 have provided a promising example of a two dimensional spin liquid state. This phase is described by a two-dimensional spinon Fermi sea coupled to a U(1) gauge field. We study Kohn-Luttinger-like pairing instabilities of the spinon Fermi surface due to singular interaction processes with twice-the-Fermi-momentum transfer. We find that under certain circumstances the pairing instability occurs in odd-orbital-angular-momentum/spin-triplet channels. Implications to experiments are discussed.