Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 43: Materials Design I

MM 43.1: Vortrag

Mittwoch, 24. März 2010, 14:45–15:00, H5

Prediction by means of an evolutionary algorithm and stability of boron sheet structures — •Silvia Schumann and Jens Kortus — TU Bergakademie Freiberg, Institute for Theoretical Physics, Leipziger Str. 23, 09596 Freiberg, Germany

There is great interest in designing new nano materials which drives theory and experiment. Similar to carbon nanotubes and graphene there are some theoretical efforts investigating boron sheets and na-notubes. So far there are no boron sheet structures found in experiment but several sheets are suggested by theory.

We present additional work in the field of predicting boron sheets as a pre-stage to boron nanotubes. Additional to analysing already known structures we used an evolutionary algorithm reproducing those structures or discovering new boron sheets. This algorithm produces a randomly chosen population of sheets which are evaluated using pseudo-potentials and plane waves to compute the free energy of each boron sheet. The more stable (lowest free energy) sheets are allowed to recombine and are mutated to form the sheets of the next generation. Promising sheets were treated with conventional structure relaxation to encounter slow convergence rates of evolutionary algorithms close to minima. We further investigated the found local minima in the energy landscape with respect to their stability by phonon calculations.