High performance Wannier interpolation of Berry curvature and related quantities with WannierBerri code

Wannier interpolation is a powerful tool for performing Brillouin zone integrals over dense grids of k points, which are essential to evaluate such quantities as the intrinsic anomalous Hall conductivity or Boltzmann transport coefficients. However, more complex physical problems and materials create harder numerical challenges, and computations with the existing codes become very expensive, which often prevents reaching the desired accuracy. In this article, I present a series of methods that boost the speed of Wannier interpolation by several orders of magnitude. They include a combination of fast and slow Fourier transforms, explicit use of symmetries, and recursive adaptive grid refinement among others. The proposed methodology has been implemented in the python code WannierBerri, which also aims to serve as a convenient platform for the future development of interpolation schemes for other phenomena.

Automated summary

Wannier interpolation is a powerful tool for performing Brillouin zone integrals over dense grids of k points, but more complex physical problems and materials create numerical challenges. This article presents methods to significantly boost the speed of Wannier interpolation, such as combining fast and slow Fourier transforms and using explicit symmetries. These methods have been implemented in the Python code WannierBerri.