Distinct local structure of superconducting Ca10M4As8(Fe2As2)5 (M=Pt,Ir)

E. Paris, T. Wakita, O. Proux, T. Yokoya, K. Kudo, D. Mitsuoka, T. Kimura, K. Fujimura, N. Nishimoto, S. Ioka, M. Nohara, Takashi Mizokawa, N. L. Saini

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    Abstract

    We have studied the local structure of superconducting Ca10Pt4As8(Fe2As2)5 (Pt10418) and Ca10Ir4As8(Fe2As2)5 (Ir10418) iron arsenides, showing different transition temperatures (Tc=38 and 16 K, respectively), by polarized Fe K-edge extended x-ray absorption fine-structure measurements. Despite the similar average crystal structures, the local structures of the FeAs4 tetrahedra in the two compounds are found to be very different. The FeAs4 in Pt10418 is close to a regular tetrahedron, while it deviates largely in Ir10418. The Fe-Fe correlations in the two compounds are characterized by similar bond-length characteristics; however, the static disorder in Pt10418 is significantly lower than that in Ir10418. The results suggest that the optimized local structure and reduced disorder are the reasons for higher Tc and well-defined electronic states in Pt10418 unlike Ir10418 showing the coexistence of glassy and normal electrons at the Fermi surface, and hence provide direct evidence of the local-structure-driven optimization of the electronic structure and superconductivity in iron arsenides.

    Original languageEnglish
    Article number224507
    JournalPhysical Review B
    Volume96
    Issue number22
    DOIs
    Publication statusPublished - 2017 Dec 15

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    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

    Cite this

    Paris, E., Wakita, T., Proux, O., Yokoya, T., Kudo, K., Mitsuoka, D., Kimura, T., Fujimura, K., Nishimoto, N., Ioka, S., Nohara, M., Mizokawa, T., & Saini, N. L. (2017). Distinct local structure of superconducting Ca10M4As8(Fe2As2)5 (M=Pt,Ir). Physical Review B, 96(22), [224507]. https://doi.org/10.1103/PhysRevB.96.224507