@article{cc128d1d763d4e3697f9caae1d3e05e0,
title = "Direct imaging of doped fluorine in LaFeAsO1-xFx superconductor by atomic scale spectroscopy",
abstract = "We report direct observation of fluorine ion dopants in the recently discovered LaFeAsO1-xFx superconductor, where the doping is critical for the superconductivity. Employing spectroscopic imaging based on scanning transmission electron microscopy, the spatial distribution of the doped fluorine ions, which are invisible in Z-contrast imaging, is clearly visualized with atomic-scale resolution. The observation directly proves that fluorine substitutes into the oxygen site in the superconducting LaFeAsO 1-xFx compound. Our results demonstrate the potential of the present method for revealing dopants undetectable by conventional microscopy imaging.",
author = "Tetsuya Tohei and Teruyasu Mizoguchi and Hidenori Hiramatsu and Yoichi Kamihara and Hideo Hosono and Yuichi Ikuhara",
note = "Funding Information: The authors acknowledge T. Yamamoto, N. Shibata, and S. D. Findlay for fruitful discussions, and H. Tsunakawa, T. Ito, S. Ohtsuka, T. Saito, and N. Saito for assistance in the experiments. This work was supported by a Grant-in-Aid for Scientific Research on Priority Areas “Nano Materials Science for Atomic Scale Modification 474” from the MEXT of Japan. A part of this work was conducted in the Center for Nano Lithography and Analysis, The University of Tokyo, supported by the MEXT, Japan.",
year = "2009",
doi = "10.1063/1.3263148",
language = "English",
volume = "95",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics Publising LLC",
number = "19",
}