2023/06/13 by Tobias Zier, Zier, Tobias, Eeuwe S. Zijlstra +5
Engineering · Physics and Astronomy · #FOS: Physical sciences #Force Microscopy Techniques and Applications #Ion-surface interactions and analysis #Laser Material Processing Techniques #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2306.08159
openalex publication_date 2023/06/13 · openalex created_date 2023/06/17 · openalex updated_date 2026/07/28
An intense femtosecond-laser excitation of a solid induces highly nonthermal conditions. In materials like silicon, laser-induced bond-softening leads to a highly incoherent ionic motion and eventually nonthermal melting. But is this outcome an inevitable consequence, or can it be controlled? Here, we performed ab initio molecular dynamics simulations of crystalline silicon after timed multiple femtosecond-laser pulse excitations with fluence above the nonthermal melting threshold. Our results demonstrate an excitation mechanism that pauses nonthermal melting and creates a metastable state instead, with an electronic structure similar to the ground state. This mechanism can be generalized to other materials, potentially enabling structural and/or electronic transitions to metastable phases in the high-excitation regime. In addition, our approach could be used to switch off nonthermal contributions in experiments, allowing reliable electron-phonon coupling constants to be obtained more easily.