Competing orders and spin-density-wave instability in La(O1-xFx)FeAsJ. Dong, H. J. Zhang, G. Xu, Z. Li, G. Li, W. Z. Hu, D. Wu, G. F. Chen, X. Dai, J. L. Luo, Z. Fang and N. L. Wang
Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences - Beijing 100190, China
received 8 May 2008; accepted in final form 30 May 2008; published July 2008
published online 27 June 2008
The interplay between different ordered phases, such as superconducting, charge or spin ordered phases, is of central interest in condensed-matter physics. The very recent discovery of superconductivity with a remarkable Tc = 26 K in Fe-based oxypnictide La(O1-xFx)FeAs (see KAMIHARA Y. et al., J. Am. Chem. Soc., 130 (2008) 3296) is a surprise to the scientific community and has generated tremendous interest. The pure LaOFeAs itself is not superconducting but shows an anomaly near 150 K in both resistivity and dc magnetic susceptibility. Here we provide combined experimental and theoretical evidences showing that a spin-density-wave (SDW) state develops at low temperature, in association with electron Nematic order. The electron-doping by F suppresses the SDW instability and induces the superconductivity. Therefore, the La(O1-xFx)FeAs offers an exciting new system showing competing orders in layered compounds.
74.70.-b - Superconducting materials.
75.30.Fv - Spin-density waves.
74.25.Jb - Electronic structure.
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