Accuracy and transferability of GAP models for tungsten
Wojciech J. Szlachta, Albert P. Bartok, and Gabor Csanyi
We introduce interatomic potentials for tungsten in the bcc crystal phase and its defects within the Gaussian Approximation Potential (GAP) framework, fitted to a database of first principles density functional calculations. We investigate the performance of a number of models based on a series of databases of increasing coverage in configuration space and showcase our strategy of choosing representative small unit cells to train models that predict properties only observable using thousands of atoms. The most comprehensive model is then used to calculate properties of the screw dislocation, including its structure, the Peierls barrier and the energetics of the vacancy-dislocation interaction.
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