Nuclear magnetic relaxation and superfluid density in Fe-pnictide superconductors; An Anisotropic -wave scenario

Nagai, Yuki*   ; Hayashi, Nobuhiko; Nakai, Noriyuki; Nakamura, Hiroki  ; Okumura, Masahiko   ; Machida, Masahiko  

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 s-wave superconductivity consistently explains experimental observations. In our phenomenological model, the gaps are assumed to be anisotropic on the electron-like Fermi surfaces around the M point, where the maximum of the anisotropic gap is about four times larger than the minimum.