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MM: Fachverband Metall- und Materialphysik

MM 6: Materials Design II

MM 6.1: Vortrag

Montag, 23. März 2009, 12:00–12:15, IFW D

Application of evolutionary strategies to crystal structure prediction — •Silvia Schumann and Jens Kortus — TU Bergakademie Freiberg, Institute for Theoretical Physics, Leipziger Str. 23, 09599 Freiberg, Germany

This work presents first tests of an evolution strategy for crystal structure prediction. For evaluation we chose elements of the third main group of the periodic system of elements, excluding boron. The crystal structures of these elements at ambient pressure are well known and have been selected because they have considerably different space groups, despite their same isovalent electronic structure and their similar chemistry.

For the evolution strategy a randomly chosen population of lattices is evaluated using pseudo-potentials to compute the free energy of each lattice. The more stable (lowest free energy) lattices are allowed to recombine and are mutated to form the lattices of the next generation. Contrary to conventional minimization methods the evolution strategy avoids trapping in local minima and provides a wide-range search of the high-dimensional search space. Possible slow convergence rates of evolution strategies close to minima are countered by applying conventional structure relaxation.