Archivio Istituzionale della RicercaPoint-contact Andreev-reflection (PCAR) experiments were performed in the Fe-1111 layered superconductor LaFeAsO0.9F0.1 with resistive T c on = 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.
Two-gap superconductivity in the Fe-1111 superconductor LaFeAsO1−xFx: A point-contact Andreev-reflection study / Gonnelli, Renato; Tortello, Mauro; Daghero, Dario; Ummarino, Giovanni; Stepanov, V. A.; Kim, J. S.. - In: CENTRAL EUROPEAN JOURNAL OF PHYSICS. - ISSN 1895-1082. - STAMPA. - 7:2(2009), pp. 251-256. [10.2478/s11534-009-0017-9]
Two-gap superconductivity in the Fe-1111 superconductor LaFeAsO1−xFx: A point-contact Andreev-reflection study
GONNELLI, Renato;TORTELLO, MAURO;DAGHERO, Dario;UMMARINO, Giovanni;
2009
Abstract
Point-contact Andreev-reflection (PCAR) experiments were performed in the Fe-1111 layered superconductor LaFeAsO0.9F0.1 with resistive T c on = 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.
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https://hdl.handle.net/11583/2278078
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