Competition between Superconductivity and Nematic Order: Anisotropy of Superconducting Coherence Length

Abstract

We study the interplay between nematic order and superconductivity, motivated by a recent experiment on FeSe observing strongly distorted vortex shapes [Song et al. Science 332 1410 (2011)]. We show that the nematic order strongly enhances the anisotropy in the superconducting coherence length, beyond that expected from considerations of the Ginzburg-Landau theory. We obtain universal functions describing the coupling between the nematic order and superconductivity, and discuss connections of our results to the experiments.