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X-ray study of femtosecond structural dynamics in the 2D charge density wave compound 1T-TaS2
- Source :
- Physica B: Condensed Matter, Physica B: Condensed Matter, Elsevier, 2015, 460, pp.100-104. ⟨10.1016/j.physb.2014.11.049⟩, Physica B: Condensed Matter, 2015, 460, pp.100-104. ⟨10.1016/j.physb.2014.11.049⟩
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- 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.
- Subjects :
- Diffraction
Phase transition
Materials science
Photon
Condensed matter physics
Phase (waves)
02 engineering and technology
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
Molecular physics
Electronic, Optical and Magnetic Materials
Amplitude
0103 physical sciences
Femtosecond
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]
Electrical and Electronic Engineering
010306 general physics
0210 nano-technology
Charge density wave
ComputingMilieux_MISCELLANEOUS
Excitation
Subjects
Details
- ISSN :
- 09214526 and 18732135
- Volume :
- 460
- Database :
- OpenAIRE
- Journal :
- Physica B: Condensed Matter
- Accession number :
- edsair.doi.dedup.....d5e92ef0ea9097673ca4ce882a232dfd