Aca - Departamento de Física - Universidad Técnica Federico Santa ...

V Encuentro Sud Americano de Colisiones Inelásticas en la Materia
Atomistic simulations of swift ion bombardment
Eduardo M. Bringa 1
1 CONICET & Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
email address corresponding author: ebringa@yahoo.com
Atomistic simulations are often used
to study the bombardment of ions in the regime
where elastic collisions dominate, but
they rarely model bombardment when electronic
effects dominate energy deposition in
the target. There are several models to include
these electronic effects within classic
molecular dynamics (MD) simulations like
Coulomb explosions, “thermal spikes”, and
etcetera. MD simulations follow the evolution
of a system of atoms interacting trough
some empirical potential. Using current parallel
computers millions of atoms can be
followed during tens of picoseconds. Such
systems are large enough and can be studied
long enough to account for the early stages
of radiation damage. Later stages have to be
studied with other techniques, like kinetic
Monte Carlo or rate theory.
Ion tracks [1], surface craters [2] or
hillocks, electronic sputtering [3], and other
radiation damage indicators can be predicted
in this way. Examples from materials
science, surface physics, and astrophysics
will be shown to illustrate that these models
are relatively simple, but provide a reasonable
description of experimental results when
electronic stopping power cannot be neglected.
Future directions to describe electronic
effects in atomistic simulations will
also be discussed.
This work has been carried out in
collaboration with several people, including
D. Schwen, D. Farkas, J. Monk, A.
Caro, J. Rodriguez-Nieva, T. Cassidy,
R.E. Johnson, R. Papaléo, M. Da Silva, C.
Ruestes, and Nestor Arista.
Figure 1. MD simulation of hillocks in tetrahedral
amorphous carbon, showing increasing hillock
height with increasing electronic stopping [4].
References
[1] R. Devanathana, P. Durhamb, J. Dua, L.R.
Corrales and E.M. Bringa, Nuclear Instruments
and Methods in Physics Research Section B 255,
172 (2007).
[2] E.M. Bringa, R.E. Johnson, R. M. Papaléo,
Phys. Rev. B 65, 094113 (2002).
[3] E.M. Bringa and R.E. Johnson, Phys. Rev.
Lett. 88, 165501 (2002).
[4] D. Schwen and E.M. Bringa, submitted
(2010).
18 Valparaíso, Chile