2024/01/18 by Bernd Bauerhenne, Bauerhenne, Bernd, Martı́n E. Garcia +1
Engineering · Physics and Astronomy · #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Laser Material Processing Techniques #Laser-Matter Interactions and Applications #Laser-induced spectroscopy and plasma #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2401.09922
openalex publication_date 2024/01/18 · openalex created_date 2024/01/20 · openalex updated_date 2026/07/28
The ultrafast dynamics of ions in solids following intense femtosecond laser excitation is governed by two fundamentally distinct yet interplaying effects. On one hand, the significant generation of hot electron-hole pairs by the light pulse alters the strength and nature of interatomic bonding, resulting in nonthermal ionic motion. On the other hand, incoherent electron-ion collisions drives an equilibration of the electrons and the ions, which reach a common temperature on a picosecond timescale. This letter introduces, for the first time, a unified theory that comprehensively accounts for both phenomena. Our approach is versatile, applicable to both ab-initio and large-scale molecular dynamics simulations, and leads to a generalization of the two-temperature model-molecular-dynamics equations of motion. To illustrate the effectiveness of our method, we apply it to describe the laser excitation of silicon thin films. Our simulations reproduce the time evolution of the Bragg peaks in excellent agreement with the experiments.