Berlin 2018 – wissenschaftliches Programm
KFM 26.4: Vortrag
Donnerstag, 15. März 2018, 16:10–16:30, EMH 025
Simulation of Ion Beam induced Surface Dynamics — •Alrik Stegmaier and Hans Hofsäss — 2. Physikalisches Institut, Georg-August Universität Goettingen
Structuring of surfaces through ion beam irradiation can be used to create self organizing dune-like waves, dimples, flat surfaces or chaotic patterns. The final structures are a result of the interplay of sputtering, redeposition, projectile implantation, transport and viscous flow, void/bubble formation and the initial surface conditions.
Accurate simulations of structuring are possible through molecular dynamics simulations, but these simulations are computationally too expensive to allow for a prediction of up to micrometer scale structure. A much faster approach is available through the use of continuum models. For this the net effect of the irradiation is expressed as the local change in surface height as a function of and up to forth order spacial derivatives of the local surface height. Typically the resulting equations of motion are taylor-expanded up to second order. Such an approach can be accurate when the surface is relatively flat and shadowing is not important, but the parameters often need to be empirically readjusted for experiments at different impact angles, ion energies or materials.
Here we present a new software package that allows for the rapid simulation of surface dynamics for arbitrary, nonlinear equations of motion that can also include nonlocal effects. With this software we explore nonlinear expansions to some of the common models, the effects of shadowing at flat impact angles and parameter determination through binary collision approximation simulation.