Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser.
Science
; 357(6346): 71-75, 2017 07 07.
Article
em En
| MEDLINE
| ID: mdl-28684521
ABSTRACT
The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a "coherent lock-in" measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Science
Ano de publicação:
2017
Tipo de documento:
Article