Nuclear magnetic relaxation and superfluid density in Fe-pnictide superconductors: An anisotropic \pm s-wave scenario

TL;DR

This paper demonstrates that an anisotropic  s-wave superconducting gap model explains nuclear magnetic relaxation and superfluid density measurements in Fe-based superconductors, highlighting the importance of gap anisotropy.

Contribution

It introduces a phenomenological five-band model with anisotropic gaps on electron-like Fermi surfaces to explain experimental data.

Findings

Anisotropic  s-wave pairing explains experimental observations

Maximum gap is about four times larger than minimum on electron Fermi surfaces

Fully-gapped anisotropic superconductivity is consistent with measurements

Abstract

We discuss the nuclear magnetic relaxation rate and the superfluid density with the use of the effective five-band model by Kuroki et al. [Phys. Rev. Lett. 101, 087004 (2008)] in Fe-based superconductors. We show that a fully-gapped anisotropic \pm s-wave superconductivity consistently explains experimental observations. In our phenomenological model, the gaps are assumed to be anisotropic on the electron-like \beta Fermi surfaces around the M point, where the maximum of the anisotropic gap is about four times larger than the minimum.