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arXiv · 1607.08197

Interrogating the superconductor Ca10(Pt4As8)(Fe2-xPtxAs2)5 Layer-by-layer

Jisun Kim·Hyoungdo Nam·Guorong Li·A. B. Karki·Zhen Wang·Yimei Zhu·Chih-Kang Shih·Jiandi Zhang·Rongying Jin·E. W. Plummer
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Abstract

Ever since the discovery of high-Tc superconductivity in layered cuprates, the roles that individual layers play have been debated, due to difficulty in layer-by-layer characterization. While there is similar challenge in many Fe-based layered superconductors, the newly-discovered Ca10(Pt4As8)(Fe2As2)5 provides opportunities to explore superconductivity layer by layer, because it contains both superconducting building blocks (Fe2As2 layers) and intermediate Pt4As8 layers. Cleaving a single crystal under ultra-high vacuum results in multiple terminations: an ordered Pt4As8 layer, two reconstructed Ca layers on the top of a Pt4As8 layer, and disordered Ca layer on the top of Fe2As2 layer. The electronic properties of individual layers are studied using scanning tunneling microscopy/spectroscopy (STM/S), which reveals different spectra for each surface. Remarkably superconducting coherence peaks are seen only on the ordered Ca/Pt4As8 layer. Our results indicate that an ordered structure with proper charge balance is required in order to preserve superconductivity.

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Jisun Kim, Hyoungdo Nam, Guorong Li, A. B. Karki, Zhen Wang, Yimei Zhu, Chih-Kang Shih, Jiandi Zhang, Rongying Jin, E. W. Plummer. 2016-07-27. Interrogating the superconductor Ca10(Pt4As8)(Fe2-xPtxAs2)5 Layer-by-layer. https://doi.org/10.1038/srep35365

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