Details

Autor(en) / Beteiligte

• Gerber, S.
• Yang, S.-L.
• Zhu, D.
• Soifer, H.
• Sobota, J. A.
• Rebec, S.
• Lee, J. J.
• Jia, T.
• Moritz, B.
• Jia, C.
• Gauthier, A.
• Li, Y.
• Leuenberger, D.
• Zhang, Y.
• Chaix, L.
• Li, W.
• Jang, H.
• Lee, J.-S.
• Yi, M.
• Dakovski, G. L.
• Song, S.
• Glownia, J. M.
• Nelson, S.
• Kim, K. W.
• Chuang, Y.-D.
• Hussain, Z.
• Moore, R. G.
• Devereaux, T. P.
• Lee, W.-S.
• Kirchmann, P. S.
• Shen, Z.-X.

Titel

Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser

Ist Teil von

• Science (American Association for the Advancement of Science), 2017-07, Vol.357 (6346), p.71-75

Ort / Verlag

United States: American Association for the Advancement of Science

Erscheinungsjahr

2017

Quelle

American Association for the Advancement of Science

Beschreibungen/Notizen

• 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.