Center for Functional Nanomaterials Seminar

Recently, a first-principles calculation of the anomalous Hall conductivity (AHC) of Fe as a Brillouin-zone integral of the Berry curvature was carried out and found to be in reasonable agreement with experimental results. However, these authors observed extraordinarily strong and rapid variations of the Berry curvature with wavevector in the vicinity of avoided crossings and near-degeneracies in reciprocal space. A conventional first-principles calculation thus requires an extremely dense k-point mesh and is quite time-consuming. Here, we present an efficient first-principles approach for computing the AHC based on Wannier interpolation. First, a conventional electronic-structure calculation is performed with spin-orbit included, on a relatively coarse k-point mesh. Second, maximally-localized Wannier functions are constructed by a post-processing step. Finally, the needed quantities such as Berry potentials and curvatures are interpolated onto a fine k-point mesh and used to compute the AHC. Our approach gives good agreement with conventional, less efficient first-priciples calculations.