Point-Contact Spectroscopy of Iron-Based Layered Superconductor   LaO$_{0.9}$F$_{0.1-\delta}$FeAs
  We present point-contact spectroscopy data for junctions between a normal metal and the newly discovered F-doped superconductor LaO$_{0.9}$F$_{0.1-\delta}$FeAs (F-LaOFeAs). A zero-bias conductance peak was observed and its shape and magnitude suggests the presence of Andreev bound states at the surface of F-LaOFeAs, which provides a possible evidence of an unconventional pairing symmetry with a nodal gap function. The maximum gap value $\Delta_0\approx3.9\pm0.7$meV was determined from the measured spectra, in good agreement with the recent experiments on specific heat and lower critical field. 
Lei Shan, Yonglei Wang, Xiyu Zhu, Gang Mu, Lei Fang, Cong Ren, Hai-Hu   Wen