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Article Dans Une Revue Journal of Physics: Condensed Matter Année : 2010

Disorder effects in pnictides: a tunneling spectroscopy study

Résumé

We present the synthesis and the tunneling spectroscopy study of superconducting FeSe(0.5)Te(0.5) (T(c) = 14 K), SmFeAsO(0.85) (T(c) = 54 K) and SmFeAsO(0.9)F(0.1) (T(c) = 45 K). The samples were characterized by Rietveld refinement of x-ray diffraction patterns and transport as well as temperature-dependent magnetic measurements. Tunneling experiments on FeSe(0.5)Te(0.5) revealed a single superconducting gap similar to 1 meV in BCS-like tunneling conductance spectra. In SmFeAsO(0.85) and SmFeAsO(0.9)F(0.1), however, more complex spectra were observed, characterized by two gap-like structures at similar to 4 and similar to 10 meV. These spectra are qualitatively understood assuming a two-band superconductor with a 's +/-' order parameter. We show that, depending on the sign relation between the pairing amplitudes in the two bands, the interband quasiparticle scattering has a crucial effect on the shape of the tunneling spectra. On the other hand, single-gap spectra found in FeSe(0.5)Te(0.5) are more compatible with a disorder-induced 's'-wave gap, due to the Se-Te substitution.

Dates et versions

hal-00648698 , version 1 (01-06-2022)

Identifiants

Citer

Yves Noat, Tristan Cren, Vincent Dubost, S. Lange, François Debontridder, et al.. Disorder effects in pnictides: a tunneling spectroscopy study. Journal of Physics: Condensed Matter, 2010, 22 (46), pp.465701. ⟨10.1088/0953-8984/22/46/465701⟩. ⟨hal-00648698⟩
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