Neural network approach for a rapid prediction of metal-supported borophene properties
We develop a high-dimensional neural network potential (NNP) to describe the structural and energetic properties of borophene deposited on silver. This NNP has the accuracy of DFT calculations while achieving computational speedups of several orders of magnitude, allowing the study of extensive structures that may reveal intriguing moiré patterns or surface corrugations. We describe an efficient approach to constructing the training data set using an iterative technique known as the "adaptive learning approach". The developed NNP potential is able to produce, with an excellent agreement, the structure, energy and forces of DFT. Finally, the calculated stability of various borophene polymorphs, including those not initially included in the training dataset, shows better stabilization for $ν\sim0.1$ hole density, and in particular for the allotrope $α$ ($ν=\frac{1}{9}$). The stability of borophene on the metal surface is shown to depend on its orientation, implying structural corrugation patterns that can only be observed from long time simulations on extended systems. The NNP also demonstrates its ability to simulate vibrational densities of states and produce realistic structures, with simulated STM images closely matching the experimental ones.