Ultrafast transient response and electron-phonon coupling in the iron-pnictide superconductor Ba(Fe1−xCox)2As2
In: ISSN: 1098-0121 ; EISSN: 1550-235X, 2010
academicJournal
Zugriff:
International audience ; The transient response of Ba(Fe1−xCox)2As2, x=0.08 was studied by pump-probe optical reflectivity. After ultrafast photoexcitation, hot electrons were found to relax with two different characteristic times, indicating the presence of two distinct decay channels: a faster one, of less than 1 ps in the considered pump fluence range and a slower one, corresponding to lattice thermalization and lasting ≅6 ps. Our analysis indicates that the fast relaxation should be attributed to preferential scattering of the electrons with only a subset of the lattice-vibration modes with a second moment of the Eliashberg function λ⟨ω^2⟩≅64 meV^2. The simultaneous excitation of a strong fully symmetric A1g optical phonon corroborates this conclusion and makes it possible to deduce the value of λ≅0.12. This small value for the electron-phonon coupling confirms that a phonon-mediated process cannot be the only mechanism leading to the formation of superconducting pairs in this family of pnictides.
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Ultrafast transient response and electron-phonon coupling in the iron-pnictide superconductor Ba(Fe1−xCox)2As2
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Autor/in / Beteiligte Person: | Mansart, Barbara ; Boschetto, Davide ; Savoia, A. ; Rullier-Albenque, F. ; Bouquet, F. ; Papalazarou, E. ; Forget, A. ; Colson, D. ; Rousse, Antoine ; Marsi, M. ; Laboratoire de Physique des Solides (LPS) ; Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) ; Laboratoire d'optique appliquée (LOA) ; École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS) ; Laboratoire Nano-Magnétisme et Oxydes (LNO) ; Service de physique de l'état condensé (SPEC - UMR3680) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay |
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Zeitschrift: | ISSN: 1098-0121 ; EISSN: 1550-235X, 2010 |
Veröffentlichung: | HAL CCSD ; American Physical Society, 2010 |
Medientyp: | academicJournal |
DOI: | 10.1103/PhysRevB.82.024513 |
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