Screened Coulomb interaction in the maximally localized Wannier basis

TL;DR

This paper presents a method to compute effective Coulomb interactions using maximally localized Wannier functions derived from first-principles calculations, applied to transition metals and SrVO3, with an optimization step for the Wannier functions.

Contribution

It introduces a combined approach of Wannier functions and constrained RPA to accurately calculate Coulomb interactions, including an optimization to maximize U.

Findings

Wannier functions are close to maximally localized ones after optimization

The method successfully computes Coulomb interactions for transition metals and SrVO3

Optimized Wannier functions enhance the accuracy of the interaction calculations

Abstract

We discuss a maximally localized Wannier function approach for constructing lattice models from first-principles electronic structure calculations, where the effective Coulomb interactions are calculated in the constrained random-phase-approximation. The method is applied to the 3d transition metals and a perovskite (SrVO_3). We also optimize the Wannier functions by unitary transformation so that U is maximized. Such Wannier functions unexpectedly turned out to be very close to the maximally localized ones.