Minimal Model for Study on Superconductivity in LaFeAsO1-xFx Based on ab-initio Downfolding R. Arita (Dept. Phys., Univ. Tokyo) K. Kuroki (Dept. Appl. Phys+Chem., Univ. Electro-Commun.) S. Onari (Dept. Appl. Phys., Nagoya Univ.) H. Usui (Dept. Appl. Phys+Chem., Univ. Electro-Commun.) H. Kontani (Dept. Phys., Nagoya Univ.) Y. Tanaka (Dept. Appl. Phys., Nagoya Univ.) H. Aoki (Dept. Phys., Univ. Tokyo)
LDA band structure & MaxLoc Wannier functions La 4f Fe 3d O 2p As 4p Maximally localized Wannier functions (Marzari-Vanderbilt, 97)
BZ unfolding G (p,0) (p,p) G X M
RPA result Fermi Surface Spin susceptibility yz, xz x2-y2 Spin susceptibility Diagonal element of the gap in the orbital rep. Extended s-wave also by Mazin et al 0803.2740 Qi et al 0804.4332 Daghofer et al 0805.0148 Nomura 0807.1168 Wang et al 0807.0498 Chubukov et al 0807.3735 X2-y2 orbital has the largest gap
Conclusions Model construction based on ab-initio downfolding 5-band model seems to be “minimal” Possibility of extended-s SC dx2-y2 orbital has the largest gap Referecnce: Kuroki et al, arXiv:0803.3325 to appear in Phys. Rev. Lett.