Appearance of superconductivity at the vacancy order-disorder boundary in KxFe2-ySe2

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Chunruo Duan
  • Junjie Yang
  • Yang Ren
  • Sean M. Thomas
  • Despina Louca

Detail(s)

Original languageEnglish
Article number184502
Journal / PublicationPhysical Review B
Volume97
Issue number18
Publication statusPublished - 14 May 2018
Externally publishedYes

Abstract

The role of phase separation and the effect of Fe-vacancy ordering in the emergence of superconductivity in alkali metal doped iron selenides AxFe2-ySe2 (A = K, Rb, Cs) is explored. High energy x-ray diffraction and Monte Carlo simulation were used to investigate the crystal structure of quenched superconducting (SC) and as-grown nonsuperconducting (NSC) KxFe2-ySe2 single crystals. The coexistence of superlattice structures with the in-plane 2×2 K-vacancy ordering and the 5×5 Fe-vacancy ordering were observed in both the SC and NSC crystals alongside the I4/mmm Fe-vacancy-free phase. Moreover, in the SC crystals, an Fe-vacancy-disordered phase is additionally proposed to be present. Monte Carlo simulations suggest that it appears at the boundary between the I4/mmm vacancy-free phase and the I4/m vacancy-ordered phases (5×5). The vacancy-disordered phase is nonmagnetic and is most likely the host of superconductivity.

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Citation Format(s)

Appearance of superconductivity at the vacancy order-disorder boundary in KxFe2-ySe2. / Duan, Chunruo; Yang, Junjie; Ren, Yang; Thomas, Sean M.; Louca, Despina.

In: Physical Review B, Vol. 97, No. 18, 184502, 14.05.2018.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review