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Direct Evidence of Two Superconducting Gaps in FeSe$_{0.5}$Te$_{0.5}$: SnS-Andreev Spectroscopy and Lower Critical Field

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 نشر من قبل S. A. Kuzmichev
 تاريخ النشر 2017
  مجال البحث فيزياء
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We present direct measurements of the superconducting order parameter in nearly optimal FeSe$_{0.5}$Te$_{0.5}$ single crystals with critical temperature $T_C approx 14$ K. Using intrinsic multiple Andreev reflection effect (IMARE) spectroscopy and measurements of lower critical field, we directly determined two superconducting gaps, $Delta_L approx 3.3 - 3.4$ meV and $Delta_S approx 1$ meV, and their temperature dependences. We show that a two-band model fits well the experimental data. The estimated electron-boson coupling constants indicate a strong intraband and a moderate interband interaction.



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