BoltzWann: A code for the evaluation of thermoelectric and electronic transport properties with a maximally-localized Wannier functions basis

TL;DR

BoltzWann is a new computational tool that efficiently evaluates thermoelectric and electronic transport properties using maximally-localized Wannier functions, achieving high accuracy with moderate computational effort.

Contribution

The paper introduces BoltzWann, a code that utilizes Wannier functions for accurate and efficient calculation of transport properties in extended systems.

Findings

High accuracy in Brillouin zone integrals

Effective handling of band crossings in derivatives

Validated on skutterudite materials

Abstract

We present a new code to evaluate thermoelectric and electronic transport properties of extended systems with a maximally-localized Wannier function basis set. The semiclassical Boltzmann transport equations for the homogeneous infinite system are solved in the constant relaxation-time approximation and band energies and band derivatives are obtained via Wannier interpolations. Thanks to the exponential localization of the Wannier functions obtained, very high accuracy in the Brillouin zone integrals can be achieved with very moderate computational costs. Moreover, the analytical expression for the band derivatives in the Wannier basis resolves any issues that may occur when evaluating derivatives near band crossings. The code is tested on binary and ternary skutterudites CoSb_3 and CoGe_{3/2}S_{3/2}.