Measurement of a Sign-Changing Two-Gap Superconducting Phase in Electron-DopedBa(Fe1−xCox)2As2Single Crystals Using Scanning Tunneling Spectroscopy

2010/07/31 by M.L. Teague, M. L. Teague, Garrett Drayna +10 · 1 citation
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #cond-mat.str-el #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevlett.106.087004

published as Phys. Rev. Lett. 106, 087004 (2011) · 4 pages, 4 figures. Paper accepted for publication in Physical Review Letters. Contact author: Nai-Chang Yeh ([email protected])

arxiv created 2011/01/30 · openalex publication_date 2011/02/24 · arxiv updated 2011/03/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

Scanning tunneling spectroscopic studies of Ba(Fe_1\ensuremath-xCo_x)₂As₂ (x=0.06, 0.12) single crystals reveal direct evidence for predominantly two-gap superconductivity. These gaps decrease with increasing temperature and vanish above the superconducting transition T_c. The two-gap nature and the slightly doping- and energy-dependent quasiparticle scattering interferences near the wave vectors (\ifmmode±\else\textpm\fi\ensuremathπ, 0) and (0, \ifmmode±\else\textpm\fi\ensuremathπ) are consistent with sign-changing s-wave superconductivity. The excess zero-bias conductance and the large gap-to-T_c ratios suggest dominant unitary impurity scattering.

Citations

• Scanning tunneling spectroscopic evidence for magnetic-field–induced microscopic orders in the high-T c superconductor YBa 2 Cu 3 O 7- δ
• A BCS-like gap in the superconductor SmFeAsO0.85F0.15
• Multiband magnetism and superconductivity in Fe-based compounds
• Superconductivity at 22 K in Co-DopedBaFe2As2Crystals
• Observation of Fermi-surface–dependent nodeless superconducting gaps in Ba 0.6 K 0.4 Fe 2 As 2

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