Convergence and machine learning predictions of Monkhorst-Pack k-points and plane-wave cut-off in high-throughput DFT calculations

TL;DR

This paper introduces an automatic convergence procedure for k-points and plane wave cut-off in DFT calculations, applies it to over 30,000 materials, and trains machine learning models to predict optimal parameters, streamlining high-throughput computational materials science.

Contribution

The work develops an automated convergence framework for DFT parameters and trains ML models to predict them, enhancing efficiency in high-throughput materials calculations.

Findings

Convergence criteria reliably predict optimal k-points and cut-offs.

Material properties influence convergence parameters significantly.

ML models accurately predict convergence parameters for new materials.

Abstract

In this work, we developed an automatic convergence procedure for k-points and plane wave cut-off in density functional (DFT) calculations and applied it to more than 30000 materials. The computational framework for automatic convergence can take a user-defined input as a convergence criterion. For k-points, we converged energy per cell (EPC) to 0.001 eV/cell tolerance and compared the results with those obtained using an energy per atom (EPA) convergence criteria of 0.001 eV/atom. From the analysis of our results, we could relate k-point density and plane wave cut-off to material parameters such as density, the slope of bands, number of band-crossings, the maximum plane-wave cut-off used in pseudopotential generation, crystal systems, and the number of unique species in materials. We also identified some material species that would require more careful convergence than others. Moreover, we statistically investigated the dependence of k-points and cutoff on exchange-correlation functionals. We utilized all this data to train machine learning models to predict the k-point line density and plane-wave cut-off for generalized materials. This would provide users with a good starting point towards converged DFT calculations. The code used, and the converged data are available on the following websites: https://jarvis.nist.gov/, and https://github.com/usnistgov/jarvis .