Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 46: Ultra-fast phenomena

HL 46.3: Talk

Friday, April 5, 2019, 10:00–10:15, H31

Diffuse scattering in a laser controlled state above the melting threshold — •Tobias Zier, Sabrina Schuster, Eeuwe S. Zijstra, and Martin E. Garcia — Theoretische Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany

With recent time-resolved x-ray diffraction techniques it became possible to measure, besides Bragg diffraction peaks, time-dependent diffuse scattering signals. Within these signals important information about the atomic motion after a femtosecond-laser excitation are included, which are mandatory to distinguish, e.g., coherent phonon motion from thermally squeezed one. Here, we analyze the diffuse scattering of bulk silicon in a laser-controlled state in the nonthermal melting region, by performing ab initio dynamics simulations using CHIVES (Code for Highly excIted Valence Electron Systems). Even though, nonthermal melting is a stochastic process we developed a control mechanism that enables us to drive the system above the nonthermal melting threshold into a stable state. Characteristic for this new state are different electronic properties compared to the ground state. Our results will give new insights into the atomic configuration within the control mechanism.