Spin-Triplet Pairing Instability of the Spinon Fermi Surface in a U(1) Spin Liquid

摘要

Recent experiments on the organic compound κ-(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 or spin-triplet channels. Implications to experiments are discussed.