Point-contact spectroscopy of iron-based layered superconductorLei Shan, Yonglei Wang, Xiyu Zhu, Gang Mu, Lei Fang, Cong Ren and Hai-Hu Wen
National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences - P.O. Box 603, Beijing 100190, China
received 12 May 2008; accepted in final form 17 July 2008; published September 2008
published online 27 August 2008
We present point-contact spectroscopy data for junctions between a normal metal and the newly discovered F-doped superconductor (F-LaOFeAs). A zero-bias conductance peak was observed and its shape and magnitude suggest 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 3.90.7 meV was determined from the measured spectra, in good agreement with the recent experiments on specific heat and lower critical field.
74.20.Rp - Pairing symmetries (other than s-wave).
74.50.+r - Tunneling phenomena; point contacts, weak links, Josephson effects.
74.70.Dd - Ternary, quaternary, and multinary compounds (including Chevrel phases, borocarbides, etc.).
© EPLA 2008