Simulations of pressure-induced structural transitions in crystals by metadynamics

In the talk I will review the application of the metadynamics method [1] to simulations of structural phase transitions in crystals [2,3]. Pressure-induced first-order structural transitions in crystals often have a character of rare events due to presence of substantial free-energy barriers, and are characterized by large hysteresis. This problem becomes particularly severe in computer simulations where the available time scale is much shorter compared to the experimental one. In Refs.[2,3] the generic metadynamics algorithm was applied to this problem employing the vectors of the simulation supercell as order parameters. I will present in detail the basic ideas and implementation of this approach and will illustrate its applications on a number of examples (for review see Refs. [4,5]).Reference:[1] A. Laio and M. Parrinello, Proc. Natl. Acad. Sci. USA 99, 12562 (2002).[2] R. Martoňák, A. Laio, and M. Parrinello, Phys. Rev. Lett. 90, 075503 (2003).[3] R. Martoňák, D. Donadio, A. R. Oganov, and M. Parrinello, Nature Materials 5, 623 (2006).[4] R. Martoňák, Eur. Phys. J. B 79, 241 (2011).[5] R. Martoňák, in Modern Methods of Crystal Structure Prediction, edited by A. R. Oganov (Wiley-VCH, Berlin, 2011).