Pairing gaps near ferromagnetic quantum critical points
Abstract
We address the quantum-critical behavior of a two-dimensional itinerant ferromagnetic systems described by a spin-fermion model in which fermions interact with close to critical bosonic modes. We consider Heisenberg ferromagnets, Ising ferromagnets, and the Ising nematic transition. Mean-field theory close to the quantum critical point predicts a superconducting gap with spin-triplet symmetry for the ferromagnetic systems and a singlet gap for the nematic scenario. Studying fluctuations in this ordered phase using a nonlinear sigma model, we find that these fluctuations are not suppressed by any small parameter. As a result, we find that a superconducting quasi-long-range order is still possible in the Ising-like models but long-range order is destroyed in Heisenberg ferromagnets.
Cite
@article{arxiv.1411.4055,
title = {Pairing gaps near ferromagnetic quantum critical points},
author = {Matthias Einenkel and Hendrik Meier and Catherine Pépin and Konstantin B. Efetov},
journal= {arXiv preprint arXiv:1411.4055},
year = {2015}
}
Comments
13 pages, 7 figures