Role of Arsenic in Iron-based Superconductivity at Atomic Scale

J. -X. Yin; Zheng Wu; X. X. Wu; Ang Li; Jian Li; X. Huang; J. -H. Wang; Y. Y. Zhao; C. L. Zhang; G. -F. Chen; X. -J. Liang; C. -S. Ting; J. -P. Hu; Z. Q. Wang; P. -H. Hor; P. C. Dai; H. Ding; S. H. Pan

arXiv · 1602.04956

Role of Arsenic in Iron-based Superconductivity at Atomic Scale

J. -X. Yin·Zheng Wu·X. X. Wu·Ang Li·Jian Li·X. Huang·J. -H. Wang·Y. Y. Zhao·C. L. Zhang·G. -F. Chen·X. -J. Liang·C. -S. Ting·J. -P. Hu·Z. Q. Wang·P. -H. Hor·P. C. Dai·H. Ding·S. H. Pan

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Abstract

In iron-based superconductors, a unique tri-layer Fe-As (Se, Te, P) plays an essential role in controlling the electronic properties, especially the Cooper pairing interaction. Here we use scanning tunneling microscopy/spectroscopy (STM/S) to investigate the role of arsenic atom in superconducting Ba0.4K0.6Fe2As2 by directly breaking and restoring the Fe-As structure at atomic scale. After the up-As-layer peeled away, the tunneling spectrum of the exposed iron surface reveals a shallow incoherent gap, indicating a severe suppression of superconductivity without arsenic covering. When a pair of arsenic atoms is placed on such iron surface, a localized topographic feature is formed due to Fe-As orbital hybridization, and the superconducting coherent peaks recover locally with the gap magnitude the same as that on the iron-layer fully covered by arsenic. These observations unravel the Fe-As interactions on an atomic scale and imply its essential roles in the iron-based superconductivity.

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J. -X. Yin, Zheng Wu, X. X. Wu, Ang Li, Jian Li, X. Huang, J. -H. Wang, Y. Y. Zhao, C. L. Zhang, G. -F. Chen, X. -J. Liang, C. -S. Ting, J. -P. Hu, Z. Q. Wang, P. -H. Hor, P. C. Dai, H. Ding, S. H. Pan. 2016-02-16. Role of Arsenic in Iron-based Superconductivity at Atomic Scale. https://arxiv.org/abs/1602.04956

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