New Superconductivity Dome in LaFeAsO1−xFx Accompanied by Structural Transition
YANG Jie1, ZHOU Rui1, WEI Lin-Lin1, YANG Huai-Xin1, LI Jian-Qi1, ZHAO Zhong-Xian1, ZHENG Guo-Qing1,2**
1Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190 2Department of Physics, Okayama University, Okayama 700-8530, Japan
High-temperature superconductivity is often found in the vicinity of antiferromagnetism. This is also true in LaFeAsO1−xFx (x≤0.2) and many other iron-based superconductors, which leads to proposals that superconductivity is mediated by fluctuations associated with the nearby magnetism. Here we report the discovery of a new superconductivity dome without low-energy magnetic fluctuations in LaFeAsO1−xFx with 0.25≤x≤0.75, where the maximal critical temperature Tc at xopt=0.5–0.55 is even higher than that at x ≤0.2. By nuclear magnetic resonance and transmission electron microscopy, we show that a C4 rotation symmetry-breaking structural transition takes place for x>0.5 above Tc. Our results point to a new paradigm of high temperature superconductivity.
(Magnetic properties including vortex structures and related phenomena)
引用本文:
. [J]. 中国物理快报, 2015, 32(10): 107401-107401.
YANG Jie, ZHOU Rui, WEI Lin-Lin, YANG Huai-Xin, LI Jian-Qi, ZHAO Zhong-Xian, ZHENG Guo-Qing. New Superconductivity Dome in LaFeAsO1−xFx Accompanied by Structural Transition. Chin. Phys. Lett., 2015, 32(10): 107401-107401.
2015, Vol. 32 
