Dominant superconducting correlations in a Luttinger liquid induced by spin fluctuations

Abstract

We study spin-fluctuation mediated divergent superconducting fluctuations in a Luttinger liquid proximity-coupled to a spin chain. Our study provides insight into how spin fluctuations can induce superconductivity in a strongly correlated non-Fermi liquid with repulsive electronic interactions only. The electrons in the system are governed by the Extended Hubbard Hamiltonian and are coupled to a chain of localized spins modeled by the spin-$\frac{1}{2}$ $XX$ Hamiltonian. Using a multichannel Luttinger liquid approach, we determine the phase diagram of the metal chain. We find that spin-polarized triplet superconducting correlations persist for repulsive electronic interactions for sufficiently large interchain couplings.