Superconductivity at 25 K in hole-doped (La1-xSrx)OFeAsHai-Hu Wen, Gang Mu, Lei Fang, Huan Yang and Xiyu Zhu
National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences - P.O. Box 603, Beijing 100080, PRC
received 14 March 2008; accepted in final form 17 March 2008; published April 2008
published online 26 March 2008
By partially substituting the tri-valence element La with di-valence element Sr in LaOFeAs, we introduced holes into the system. For the first time, we successfully synthesized the hole-doped new superconductors (La1-xSrx)OFeAs. The maximum superconducting transition temperature at about 25 K was observed at a doping level of x = 0.13. It is evidenced by Hall effect measurements that the conduction in this type of material is dominated by hole-like charge carriers, rather than electron-like ones. Together with the data of the electron-doped system La(O1-xFx)FeAs, a generic phase diagram is depicted and is revealed to be similar to that of the cuprate superconductors.
74.20.Mn - Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.).
74.10.+v - Occurrence, potential candidates.
74.70.Dd - Ternary, quaternary, and multinary compounds (including Chevrel phases, borocarbides, etc.).
© EPLA 2008