Excitation signatures of isochorically heated electrons in solids at finite wavenumber explored from first principles

Abstract

Ultrafast heating of solids with modern X-ray free electron lasers (XFELs) leads to a unique set of conditions that is characterized by the simultaneous presence of heated electrons in a cold ionic lattice. In this work, we analyze the effect of electronic heating on the dynamic structure factor (DSF) in bulk Aluminium (Al) with a face-centered cubic lattice and in silicon (Si) with a crystal diamond structure using first-principles linear-response time-dependent density functional theory simulations. We find a thermally induced red shift of the collective plasmon excitation in both materials. In addition, we show that the heating of the electrons in Al can lead to the formation of a double-plasmon peak due to the extension of the Landau damping region to smaller wavenumbers. Finally, we demonstrate that thermal effects generate a measurable and distinct signature (peak-valley structure) in the DSF of Si at small frequencies. Our simulations indicate that there is a variety of new features in the spectrum of X-ray-driven solids, specifically at finite momentum transfer, which can probed in upcoming X-ray Thomson scattering (XRTS) experiments at various XFEL facilities.

References in corpus (12)

• Linear density response function in the projector-augmented wave method: Applications to solids, surfaces, and interfaces
• Ab initio equations of state for hydrogen (H-REOS.3) and helium (He-REOS.3) and their implications for the interior of Brown Dwarfs
• Accurate Temperature Diagnostics for Matter under Extreme Conditions
• turboEELS -- A code for the simulation of the electron energy loss and inelastic X-ray scattering spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory
• Ab initio results for the plasmon dispersion and damping of the warm dense electron gas
• Electron-hole and plasmon excitations in 3d transition metals: Ab initio calculations and inelastic x-ray scattering measurements
• Ab initio Static Exchange-Correlation Kernel across Jacob's Ladder without functional derivatives
• Screening of a test charge in a free-electron gas at warm dense matter and dense non-ideal plasma conditions
• Linear-response time-dependent density functional theory approach to warm dense matter with adiabatic exchange--correlation kernels
• Non-empirical mixing coefficient for hybrid XC functionals from analysis of the XC kernel
• Revealing Non-equilibrium and Relaxation in Warm Dense Matter
• Averaging over atom snapshots in linear-response TDDFT of disordered systems: A case study of warm dense hydrogen

Cited by in corpus (1)

• Applying the Liouville-Lanczos Method of Time-Dependent Density-Functional Theory to Warm Dense Matter