Suppression of superconductivity by nonmagnetic disorder in organic superconductor κ-(BEDT-TTF)2Cu(NCS)2

Takahiko Sasaki, Hajime Oizumi, Yuki Honda, Naoki Yoneyama, Norio Kobayashi

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The suppression of superconductivity by nonmagnetic disorder is investigated systematically in the organic superconductor κ-(BEDT-TTF) 2Cu(NCS)2. We introduce a nonmagnetic disorder arising from molecule substitution in part with deuterated BEDT-TTF or BMDT-TTF for BEDT-TTF molecules and molecular defects introduced by X-ray irradiation. A quantitative evaluation of the scattering time τdHvA is carried out by de Haas-van Alphen (dHvA) effect measurement. A large reduction in T c with a linear dependence on 1=τdHvA is found in the small-disorder region below 1=τdHvA≃1 × 10 12 s-1 in both the BMDT-TTF molecule-substituted and X-ray-irradiated samples. The observed linear relation between Tc and 1=τdHvA is in agreement with the Abrikosov-Gorkov (AG) formula, at least in the smalldisorder region. This observation is reasonably consistent with the unconventional superconductivity proposed thus far for the present organic superconductor. A deviation from the AG formula, however, is observed in the large-disorder region above 1=τdHvA≃1 × 10 12 s-1, which reproduces the previous transport study [J. G. Analytis et al.: Phys. Rev. Lett. 96 (2006) 177002]. We present some interpretations of this deviation from the viewpoints of superconductivity and the inherent difficulties in the evaluation of scattering time.

Original languageEnglish
Article number104703
Journaljournal of the physical society of japan
Volume80
Issue number10
DOIs
Publication statusPublished - 2011 Oct 1

Keywords

  • De Haas-van Alphen oscillations
  • Disorder effect
  • Organic superconductor
  • Scattering time
  • X-ray irradiation
  • κ-(BEDT-TTF) Cu(NCS)

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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