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Measurements of nonequilibrium interatomic forces using time-domain x-ray scattering
- Publication Year :
- 2021
- Publisher :
- American Physical Society, 2021.
-
Abstract
- We demonstrate an experimental approach to determining the excited-state interatomic forces using femtosecond x-ray pulses from an x-ray free-electron laser. We determine experimentally the excited-state interatomic forces that connect photoexcited carriers to the nonequilibrium lattice dynamics in the prototypical Peierls-distorted material, bismuth. The forces are obtained by a constrained least-squares fit of a pairwise interatomic force model to the excited-state phonon dispersion relation as measured by the time- and momentum-resolved x-ray diffuse scattering. We find that photoexcited carriers weaken predominantly the nearest-neighbor forces, which drives the measured softening of the transverse acoustic modes throughout the Brillouin zone as well as the zone-center ${A}_{1g}$ optical mode. This demonstrates a bond-selective approach to measuring electron-phonon coupling relevant to a broad range of photoinduced phase transitions and transient light-driven states in quantum materials.
- Subjects :
- Phase transition
Phonon
Structural phase transition
Non-equilibrium thermodynamics
02 engineering and technology
01 natural sciences
Molecular physics
Ultrafast optics
Condensed Matter::Materials Science
Dispersion relation
0103 physical sciences
X-ray lasers
010306 general physics
Physics
Photoexcitation
Synchrotron radiation & free-electron lasers
Scattering
Electron-phonon coupling
X-ray scattering
021001 nanoscience & nanotechnology
Coupling (probability)
Brillouin zone
Peierls transition
Ultrafast pump-probe spectroscopy
Femtosecond
Phonons
0210 nano-technology
Semimetals
Nonequilibrium systems
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....69ee895f09e0ede08ffe601f225bcea9