Abstract:
Recently we developed a new metadynamics-based algorithm [1,2] for simulation of structural phase transitions in crystals which searches for low-energy pathways leading from one crystal structure to another. I will present basic ideas of the new method and illustrate its applications on several examples of inorganic as well as organic crystals. Main focus will be on the challenging case of pressure-induced transformations in silica (SiO2) which is an important system for geophysics as well as for technology. Here the new technique finally brought simulations into close agreement with experiment. This represents a substantial improvement with respect to the previous algorithms and for the first time the study of complex structural phase transitions with many intermediates is within the reach of molecular dynamics (MD) simulations.

References:
1. R. Martonak, A. Laio, M. Parrinello: Predicting crystal structures: The Parrinello-Rahman method revisited Phys. Rev. Lett. 90, 075503 (2003)
2. R. Martonak, D. Donadio, A. R. Oganov and M. Parrinello: Crystal structure transformations in SiO2 from classical and ab initio metadynamics Nature Materials, 5, 623 (2006).