Suppression of structural instability in LaOBiS2-xSex by Se substitution

E. Paris, Y. Mizuguchi, T. Wakita, K. Terashima, T. Yokoya, Takashi Mizokawa, N. L. Saini

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    4 Citations (Scopus)

    Abstract

    Isovalent substitution of S by Se in LaOBiS2-xSex has a substantial effect on its electronic structure and thermoelectric properties. To investigate the possible role of BiS2 structural instability, we have studied the local structure of LaOBiS2-xSex () using temperature dependent Bi L3-edge extended x-ray absorption fine structure measurements. The results reveal that the local structure of the two compounds is significantly different. The BiS2 sub-lattice is largely distorted in LaOBiS2 (x = 0.0), with two in-plane Bi-S1 distances separated by ∼0.4 Å instead LaOBiSSe (x = 1.0) showing much smaller local disorder with two in-plane Bi-Se distances in the plane being separated by ∼0.2 Å. Temperature dependent study shows that the two Bi-S1 distances are characterized by different bond strength in LaOBiS2 (x = 0.0) while it is similar for the Bi-Se distances in LaOBiSSe (x = 1.0). The out of plane Bi-S2 bond is harder in LaOBiSSe indicating that the structural instability of BiS2 layer has large effect on the out-of-plane atomic correlations. The results suggest that the local structure of LaOBiS2-xSex is an important factor to describe differing electronic and thermal transport of the two compounds.

    Original languageEnglish
    Article number455703
    JournalJournal of Physics Condensed Matter
    Volume30
    Issue number45
    DOIs
    Publication statusPublished - 2018 Oct 22

    Keywords

    • BiS-based materials
    • effect of substitution
    • local structure and bond characteristics
    • structural instability
    • temperature dependent EXAFS

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics

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  • Cite this

    Paris, E., Mizuguchi, Y., Wakita, T., Terashima, K., Yokoya, T., Mizokawa, T., & Saini, N. L. (2018). Suppression of structural instability in LaOBiS2-xSex by Se substitution. Journal of Physics Condensed Matter, 30(45), [455703]. https://doi.org/10.1088/1361-648X/aae501