Local structure displacements in La1−xCexOBiSSe as a function of Ce substitution

G. M. Pugliese, F. Stramaglia, F. G. Capone, M. Y. Hacisalihoglu, R. Kiyama, R. Sogabe, Y. Goto, S. Pollastri, D. Oliveira De Souza, L. Olivi, T. Mizokawa, Y. Mizuguchi, N. L. Saini

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Abstract

We have investigated the local structure of layered La1−xCexOBiSSe system by Bi L3-edge extended X-ray absorption fine structure (EXAFS) measurements for different Ce substitutions. Ce L3-edge X-ray absorption spectroscopy (XAS) has been used to evaluate the Ce valence responsible for the self-doping in this system. We have found that the local distortion, determined by the separation between two Bi-Ch distances within the BiCh2-layer (Ch=S,Se), is quickly suppressed by Ce substitution while the axial Bi-S2 bond elongates. Ce L3-edge XAS reveals a coexistence of Ce3+ and Ce4+ in which the Ce4+ weight decreases, an indication of a partial breaking of RE-S-Bi (RE=La/Ce) charge transfer channel with Ce substitution. The results suggest that interaction between REO spacer layer and BiCh2 layer, dictated by the out-of-plane Bi-S2 distance, has a significant role in triggering superconductivity in the title system, with the in-plane distortion controlling the charge mobility within the BiCh2-layer.

Original languageEnglish
Article number109648
JournalJournal of Physics and Chemistry of Solids
Volume147
DOIs
Publication statusPublished - 2020 Dec

Keywords

  • BiS2-based systems
  • Local structure
  • Self-doping
  • Superconductivity

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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    Pugliese, G. M., Stramaglia, F., Capone, F. G., Hacisalihoglu, M. Y., Kiyama, R., Sogabe, R., Goto, Y., Pollastri, S., De Souza, D. O., Olivi, L., Mizokawa, T., Mizuguchi, Y., & Saini, N. L. (2020). Local structure displacements in La1−xCexOBiSSe as a function of Ce substitution. Journal of Physics and Chemistry of Solids, 147, [109648]. https://doi.org/10.1016/j.jpcs.2020.109648