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Laulhe, C., Cario, L., Corraze, B., Janod, E., Huber, T., Lantz, G., Boulfaat, S., Ferrer, A., Mariager, S. O., Johnson, J. A., Gruebel, S., Luebcke, A., Ingold, G., Beaud, P., Johnson, S. L. & Ravy, S. (2015) X-ray study of femtosecond structural dynamics in the 2D charge density wave compound 1T-TaS2. Physica B, 460 100–104.
Added by: Laurent Cournède (2016-03-10 18:36:42) |
| Type de référence: Article DOI: 10.1016/j.physb.2014.11.049 Numéro d'identification (ISBN etc.): 0921-4526 Clé BibTeX: Laulhe2015 Voir tous les détails bibliographiques  |
Catégories: INTERNATIONAL, PMN Mots-clés: Charge density wave, crystal, diffraction, Femtosecond dynamics, localization, phase-transformations, state, Time-resolved diffraction Créateurs: Beaud, Boulfaat, Cario, Corraze, Ferrer, Gruebel, Huber, Ingold, Janod, Johnson, Johnson, Lantz, Laulhe, Luebcke, Mariager, Ravy Collection: Physica B |
Consultations : 1/533
Indice de consultation : 4% Indice de popularité : 1% |
| Résumé |
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1T-TaS2 is a 2D metallic compound which undergoes a series of electronically driven phase transitions toward charge density wave and Mott phases Its intricate electron-phonon interactions and electron-electron correlations have been promising peculiar out-of-equilibrium dynamics. In this paper, we provide the first direct information on the atomic structure response to an ultra-fast infrared laser pulse in the commensurate phase of 1T-TaS2, by using femtosecond time-resolved X-ray diffraction. We show that ultra-fast excitation with near-infrared photons drives a displacive excitation of the amplitude mode of the commensurate charge density wave. About 3 ps after laser excitation, the system reaches a new, photo induced state that is maintained for at least 10 ps. We give evidence that this long-lived state exhibits the same structural modulation as in the thermodynamically stable commensurate phase, with a large correlation length. Only the average amplitude of the modulation is found to decrease. We propose that the long-lived state is formed from the commensurate phase by reducing the modulation amplitude on few superlattice nodes. The underlying mechanism proposed is the annihilation of self trapped polarons. (C) 2014 Elsevier B.V. All rights reserved
Added by: Laurent Cournède |