Cluster-based density-functional approach to quantum transport through molecular and atomic contacts

TL;DR

This paper introduces a cluster-based density-functional method to accurately model quantum charge transport in molecular and atomic contacts by extracting bulk electrode parameters from large clusters, improving upon previous approaches.

Contribution

The paper presents a systematic way to improve electrode modeling in quantum transport calculations using large clusters, enhancing accuracy over prior methods.

Findings

Successfully applied to Au atomic chains with various configurations

Extended to single-atom Al contacts demonstrating versatility

Avoids issues with nonorthogonal basis functions

Abstract

We present a cluster-based density-functional approach to model charge transport through molecular and atomic contacts. The electronic structure of the contacts is determined in the framework of density functional theory, and the parameters needed to describe transport are extracted from finite clusters. A similar procedure, restricted to nearest-neighbor interactions in the electrodes, has been presented by Damle et al. [Chem. Phys. 281, 171 (2002)]. Here, we show how to systematically improve the description of the electrodes by extracting bulk parameters from sufficiently large metal clusters. In this way we avoid problems arising from the use of nonorthogonal basis functions. For demonstration we apply our method to electron transport through Au contacts with various atomic-chain configurations and to a single-atom contact of Al.