TY - JOUR
T1 - Distinct local structure of superconducting Ca10M4As8(Fe2As2)5 (M=Pt,Ir)
AU - Paris, E.
AU - Wakita, T.
AU - Proux, O.
AU - Yokoya, T.
AU - Kudo, K.
AU - Mitsuoka, D.
AU - Kimura, T.
AU - Fujimura, K.
AU - Nishimoto, N.
AU - Ioka, S.
AU - Nohara, M.
AU - Mizokawa, T.
AU - Saini, N. L.
N1 - Funding Information:
We thank the ESRF staff for the assistance during the measurements. A part of this work was performed at the Advanced Science Research Center, Okayama University. This work was partly supported by Grants-in-Aid for Scientific Research (Grants No. 15H05886 and No. 16K05451), the Program for Promoting the Enhancement of Research Universities from MEXT, and the Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers from JSPS. The work is a part of the executive protocol of the general agreement for cooperation between the Sapienza University of Rome and Okayama University. The work at the Sapienza University is partially supported by PRIN2012 (Grant No. 2012X3YFZ2).
Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/12/15
Y1 - 2017/12/15
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.96.224507
DO - 10.1103/PhysRevB.96.224507
M3 - Article
AN - SCOPUS:85039423652
SN - 2469-9950
VL - 96
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
IS - 22
M1 - 224507
ER -