Measurement of a sign-changing two-gap superconducting phase in electron-doped Ba(Fe(1-x)Co(x))2As2 single crystals using scanning tunneling spectroscopy.

نویسندگان

  • M L Teague
  • G K Drayna
  • G P Lockhart
  • P Cheng
  • B Shen
  • H-H Wen
  • N-C Yeh
چکیده

Scanning tunneling spectroscopic studies of Ba(Fe(1-x)Co(x))(2)As(2) (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 (±π, 0) and (0, ±π) 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.

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عنوان ژورنال:
  • Physical review letters

دوره 106 8  شماره 

صفحات  -

تاریخ انتشار 2011