Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 93: Focus Session: Structural Dynamics in Nanoscale Materials, Probed by Ultrafast Electron Pulses I
O 93.4: Talk
Thursday, March 15, 2018, 11:45–12:00, HE 101
Molecular dynamics simulations of a femtosecond laser excitation in antimony — •Bernd Bauerhenne1,2, Felipe Valencia3, and Martin E. Garcia1,2 — 1Theoretische Physik - Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany — 2Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Strasse 40, D-34132 Kassel, Germany — 3Physics Department, Universidad Nacional de Colombia, Edificio 404, Ciudad Universitaria, Bogota, Colombia
The goal of this work is to accurately simulate laser induced ultrafast, nonthermal solid-to-solid and solid-to-liquid phase transitions in Sb. In particular we are interested in elucidate the dynamics of the ultrafast transition from the A7 to the simple cubic structure in Sb, and also to investigate how fast nonthermal melting of Sb can occur for extremely high laser fluences. For this purpose, we run ab-initio molecular dynamic simulations of laser excited antimony in thin-film geometry (containing around 400 atoms) using our in house density functional theory code CHIVES. Based on these simulations and in order to allow for a closer comparison with experiments, we developed an analytical interatomic potential describing laser excited Sb. In addition, we calculated the laser-fluence dependent electron-phonon coupling constant in Sb from ab-initio calculations. Using our potential and including incoherent electron-phonon scattering, we simulated the intense femtosecond laser excitation of antimony on large supercells.