Imaging nonequilibrium atomic vibrations with x-ray diffuse scattering

Abstract

For over a century, x-ray scattering has been the most powerful tool for determining the equilibrium structure of crystalline materials. Deviations from perfect periodicity, for example due to thermal motion of the atoms, reduces the intensity of the Bragg peaks as well as produces structure in the diffuse scattering background. Analysis of the thermal diffuse scattering (TDS) had been used to determine interatomic force constants and phonon dispersion in relatively simple cases before inelastic neutron scattering became the preferred technique to study lattice dynamics. With the advent of intense synchrotron x-ray sources, there was a renewed interest in TDS for measuring phonon dispersion. The relatively short x-ray pulses emanating from these sources also enables the measurement of phonon dynamics in the time domain. Prior experiments on nonequilibrium phonons were either limited by time-resolution and/or to relatively long wavelength excitations. Here we present the first images of nonequilibrium phonons throughout the Brillouin zone in photoexcited III-V semiconductors, indium-phosphide and indium-antimonide, using picosecond time-resolved diffuse scattering. In each case, we find that the lattice remain out of equilibrium for several hundred picoseconds up to nanoseconds after laser excitation. The non-equilibrium population is dominated by transverse acoustic phonons which in InP are directed along high-symmetry directions. The results have wide implications for the detailed study of electron-phonon and phonon-phonon coupling in solids.

arXiv comment10 pages, 3 figures

Cited by in corpus (22)

• Electron-phonon coupling and energy flow in a simple metal beyond the two-temperature approximation
• Mapping momentum-dependent electron-phonon coupling and non-equilibrium phonon dynamics with ultrafast electron diffuse scattering
• Momentum-Resolved View of Electron-Phonon Coupling in Multilayer WSe${}_2$
• Toward precise simulations of the coupled ultrafast dynamics of electrons and atomic vibrations in materials
• Generation of high-frequency strain waves during femtosecond demagnetization of Fe/MgO films
• Accessing the anisotropic non-thermal phonon populations in black phosphorus
• Time- and momentum-resolved phonon population dynamics with ultrafast electron diffuse scattering
• Thermalization in simple metals: The role of electron-phonon and phonon-phonon scatterings
• Phonon Spectroscopy with Sub-meV Resolution by Femtosecond X-ray Diffuse Scattering
• Concepts and use cases for picosecond ultrasonics with x-rays
• Efficient first-principles methodology for the calculation of the all-phonon inelastic scattering in solids
• Multi-phonon diffuse scattering in solids from first-principles: Application to layered crystals and 2D materials
• Ultrafast demagnetization in ferromagnetic materials: Origins and progress
• Exchange-striction driven ultrafast nonthermal lattice dynamics in NiO
• Nonequilibrium phonon dynamics beyond the quasiequilibrium approach
• Evolution of non-thermal phonon and electron populations in photo-excited germanium on picosecond timescales
• Melting the Superconducting State in the Electron Doped Cuprate Pr${}_{1.85}$Ce${}_{0.15}$CuO${}_{4-\delta }$ with Intense near-infrared and Terahertz Pulses
• Fingerprints of hot-phonon physics in time-resolved correlated quantum lattice dynamics
• Phonon state tomography of electron correlation dynamics in optically excited solids
• Element-specific ultrafast lattice dynamics in monolayer WSe2
• Properties and challenges of hot-phonon physics in metals: MgB${}_2$ and other compounds
• Ultrafast lattice dynamics and electron-phonon coupling in platinum extracted with a global fitting approach for time-resolved polycrystalline diffraction data