Two-gap superconductivity in the Fe-1111 superconductor LaFeAsO1−x
Fx: A point-contact Andreev-reflection study

• Authors: Renato Gonnelli , Mauro Tortello , Dario Daghero , Giovanni Ummarino , Valeri Stepanov , Jun Kim
• Languages of publication: EN

Abstracts

EN

Point-contact Andreev-reflection (PCAR) experiments were performed in the Fe-1111 layered superconductor LaFeAsO0.9F0.1 with resistive T
con ∼ 27 K. The observation of two pairs of peaks in the low-temperature Andreev-reflection spectra clearly indicates the presence of two order parameters. The behavior of the two gaps as a function of temperature, obtained by fitting the conductance curves by means of the generalized two-band Blonder-Tinkham-Klapwijk model, shows some anomalies. A theoretical analysis performed within the two-band Eliashberg theory with a generic electron-boson coupling can reproduce the low-temperature value of the two gaps but generally fails in giving a satisfactory fit of their overall temperature dependence, indicating the rich and complex physics of these newly discovered superconductors.

Keywords

EN

Fe-based superconductors; point-contact Andreev-reflection spectroscopy; two-band Eliashberg theory

• Publisher: De Gruyter Open
• Journal: Open Physics
• Year: 2009
• Volume: 7
• Issue: 2
• Pages: 251-256

Dates

published

1 - 6 - 2009

online

26 - 4 - 2009

Contributors

author

Renato Gonnelli

• Dipartimento di Fisica and CNISM, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino, Italy

author

Mauro Tortello

• Dipartimento di Fisica and CNISM, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino, Italy

author

Dario Daghero

• Dipartimento di Fisica and CNISM, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino, Italy

author

Giovanni Ummarino

• Dipartimento di Fisica and CNISM, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino, Italy

author

Valeri Stepanov

• P. N. Lebedev Physical Institute, Russian Academy of Sciences, Leninskiy Prospekt 53, 119991, Moscow, Russia

author

Jun Kim

• Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany

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Identifiers

DOI

10.2478/s11534-009-0017-9