Simulating structural phase transitions with simple models

Phase transformations on the atomic scale continue to pose a challenge to structural elucidation, due to the short time and length scales involved. We employ molecular dynamics simulations to shed light on different structural transitions: between liquid phases and solid crystals, as well as between different crystalline phases. Using simple isotropic pair potentials, we have access to a wide variety of crystal structures whose formation and transformation we study. We probe transitions induced by changes in temperature or pressure, and we investigate the different pathways that phase transformations can traverse. In the process, we employ geometrical and statistical measures, both traditional as well as machine-learning enabled methods, in order to find out where, why, and how structural phase transformations occur. By understanding the processes that occur during phase transitions on a particle-by-particle level, we hope to enable a knowledge-based framework in which specific transformation pathways are targeted for the tailored design of materials.