Vacancies, disorder-induced smearing of the electronic structure, and its implications for the superconductivity of anti-perovskite MgC0.93Ni2.85

David Ernsting, David Billington, Tom Millichamp, Rebecca A. Edwards, Hazel Sparkes, ND Zhigadlo, S. R. Giblin, Jonathan Taylor, Jonathan Duffy, Stephen Dugdale

Research output: Contribution to journalArticle (Academic Journal)peer-review

4 Citations (Scopus)
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Abstract

The anti-perovskite superconductor MgC0.93Ni2.85 was studied using high-resolution x-ray Compton scattering combined with electronic structure calculations. Compton scattering measurements were used to determine experimentally a Fermi surface that showed good agreement with that of our supercell calculations, establishing the presence of the predicted hole and electron Fermi surface sheets. Our calculations indicate that the Fermi surface is smeared by the disorder due to the presence of vacancies on the C and Ni sites, but does not drastically change shape. The 20% reduction in the Fermi level density-of-states would lead to a significant (∼ 70%) suppression of the superconducting Tc for pair-forming electron-phonon coupling. However, we ascribe the observed much smaller Tc reduction at our composition (compared to the stoichiometric compound) to the suppression of pair-breaking spin fluctuations.
Original languageEnglish
Article number10148
Number of pages9
JournalScientific Reports
Volume7
DOIs
Publication statusPublished - 31 Aug 2017

Keywords

  • Electronic properties and materials
  • Superconducting properties and materials

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