Neural-Network-Based Path Collective Variables for Enhanced Sampling of Phase Transformations

J Rogal and E Schneider and ME Tuckerman, PHYSICAL REVIEW LETTERS, 123, 245701 (2019).

DOI: 10.1103/PhysRevLett.123.245701

The investigation of the microscopic processes underlying structural phase transformations in solids is extremely challenging for both simulation and experiment. Atomistic simulations of solid-solid phase transitions require extensive sampling of the corresponding high- dimensional and often rugged energy landscape. Here, we propose a rigorous construction of a 1D path collective variable that is used in combination with enhanced sampling techniques for efficient exploration of the transformation mechanisms. The path collective variable is defined in a space spanned by global classifiers that arc derived from local structural units. A reliable identification of the local structural environments is achieved by employing a neural-network-based classification scheme. The proposed path collective variable is generally applicable and enables the investigation of both transformation mechanisms and kinetics.

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