The effect of RE substitution in layered REO0.5F0.5BiS2: Chemical pressure, local disorder and superconductivity

Y. Mizuguchi, E. Paris, T. Sugimoto, A. Iadecola, J. Kajitani, O. Miura, T. Mizokawa, N. L. Saini

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33 Citations (Scopus)

Abstract

We have studied the effect of RE substitution on the structure and the local atomic disorder in REO0.5F0.5BiS2 (RE = rare-earth) to understand their correlation with the bulk superconductivity in these materials. The mean RE size, affecting the chemical pressure, has been varied in two series namely Ce1-xNdxO0.5F0.5BiS2 and Nd1-ySmyO0.5F0.5BiS2. The lattice parameters evolve anomalously, showing an anisotropic shrinkage (elongation) of the c-axis (a-axis) to an isotropic expansion of the lattice with increasing mean RE size. The Bi L3-edge extended X-ray absorption fine structure (EXAFS) measurements are performed to investigate local displacements in the BiS2 lattice, revealing a large disorder and a sharp boundary between the Ce-containing and Sm-containing series with a distinct local structure. The results suggest that the bulk superconductivity in REO0.5F0.5BiS2 is correlated with anomalous atomic displacements in the Bi-S1 network, likely to be a combined effect of active Bi 6s electronic states and a possible Jahn-Teller-like instability of the Bi 6px/6py electrons.

Original languageEnglish
Pages (from-to)22090-22096
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number34
DOIs
Publication statusPublished - 2015 Jul 20

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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