Universal $\sqrt{2}\times\sqrt{2}$ structure and short-range charge order at the surfaces of BaFe$_{2-x}$Co$_{x}$As$_{2}$ compounds with various Co doping levels

Hui Zhang; Jun Dai; Yujing Zhang; Danru Qu; Huiwen Ji; Xianhui Chen; Bing Wang; Changgan Zeng; Jinlong Yang; J. G. Hou

doi:10.1103/physrevb.81.104520

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arXiv · 0908.1710

Universal $\sqrt{2}\times\sqrt{2}$ structure and short-range charge order at the surfaces of BaFe$_{2-x}$Co$_{x}$As$_{2}$ compounds with various Co doping levels

Hui Zhang·Jun Dai·Yujing Zhang·Danru Qu·Huiwen Ji·Xianhui Chen·Bing Wang·Changgan Zeng·Jinlong Yang·J. G. Hou

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Abstract

The structure and electronic order at the cleaved (001) surfaces of the newly-discovered pnictide superconductors BaFe$_{2-x}$Co$_{x}$As$_{2}$ with x ranging from 0 to 0.32 are systematically investigated by scanning tunneling microscopy. A $\sqrt{2}\times\sqrt{2}$ surface structure is revealed for all the compounds, and is identified to be Ba layer with half Ba atoms lifted-off by combination with theoretical simulation. A universal short-range charge order is observed at this $\sqrt{2}\times\sqrt{2}$ surface associated with an energy gap of about 30 meV for all the compounds.

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Hui Zhang, Jun Dai, Yujing Zhang, Danru Qu, Huiwen Ji, Xianhui Chen, Bing Wang, Changgan Zeng, Jinlong Yang, J. G. Hou. 2009-08-12. Universal $\sqrt{2}\times\sqrt{2}$ structure and short-range charge order at the surfaces of BaFe$_{2-x}$Co$_{x}$As$_{2}$ compounds with various Co doping levels. https://doi.org/10.1103/physrevb.81.104520

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