Superconducting Gap and Pseudogap in Iron-Based Layered Superconductor La(O1-xFx)FeAs

We report high-resolution photoemission spectroscopy of newly-discovered iron-based layered superconductor La(O_0.93F_0.07)FeAs (T_c = 24 K). We found that the superconducting gap shows a marked deviation from the isotropic s-wave symmetry. The estimated gap size at 5 K is 3.6 meV in the s- or axial p-wave case, while it is 4.1 meV in the polar p- or d-wave case. We also found a pseudogap of 15-20 meV above T_c, which is gradually filled-in with increasing temperature and closes at temperature far above T_c similarly to copper-oxide high-temperature superconductors.