Doping-dependent phase diagram of LaOMAs (M=V-Cu) and electron-type superconductivity near ferromagnetic instabilityG. Xu1, W. Ming1, Y. Yao1, X. Dai1, S.-C. Zhang2 and Z. Fang1
1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences Beijing 100190, China
2 Department of Physics, Stanford University - Stanford, CA 94305-4045, USA
received 21 April 2008; accepted in final form 29 April 2008; published June 2008
published online 3 June 2008
By first-principles calculations, we present a doping-dependent phase diagram of the LaOMAs (M = V - Cu) family. It is characterized as a antiferromagnetic semiconductor around the LaOMnAs side and as a ferromagnetic metal around LaOCoAs. Both LaOFeAs and LaONiAs, where superconductivity were discovered, are located at the borderline of magnetic phases. An extensive Fermi surface analysis suggests that the observed superconductivity is of electron type in its origin. We discuss possible pairing mechanisms in the context of competing ferromagnetic phases found in this work and the ferromagnetic spin fluctuations.
74.70.-b - Superconducting materials.
74.25.Jb - Electronic structure.
74.25.Ha - Magnetic properties.
© EPLA 2008