Simple and efficient way of speeding up transmission calculations with $k$-point sampling

TL;DR

The paper introduces a simple, low-cost post-processing method to interpolate transmission functions over k-points, significantly speeding up calculations in electron and phonon transport simulations.

Contribution

It proposes a novel interpolation scheme that enhances the efficiency of transmission calculations in first principles transport studies.

Findings

Achieves about tenfold speed-up in graphene transport calculations.

Produces smooth, well-converged transmission functions from fewer k-points.

Applicable to first principles calculations with periodic boundary conditions.

Abstract

The transmissions as functions of energy are central for electron or phonon transport in the Landauer transport picture. We suggest a simple and computationally "cheap" post-processing scheme to interpolate transmission functions over $k$-points to get smooth well-converged average transmission functions. This is relevant for data obtained using typical "expensive" first principles calculations where the leads/electrodes are described by periodic boundary conditions. We show examples of transport in graphene structures where a speed-up of an order of magnitude is easily obtained.