Pride, Prejudice, and Penury of {\it ab initio} transport calculations for single molecules

TL;DR

This paper reviews the foundations and challenges of ab initio transport calculations for single molecules, focusing on time-dependent density functional theory and addressing reliability issues in low conductance regimes.

Contribution

It provides a critical overview of the standard method for molecular transport calculations, highlighting pitfalls and applicability limitations.

Findings

Identification of key pitfalls in ab initio transport calculations

Discussion of the domain of applicability of the standard method

Insights into the reliability of molecular conductance predictions

Abstract

Recent progress in measuring the transport properties of individual molecules has triggered a substantial demand for {\it ab initio} transport calculations. Even though program packages are commercially available and placed on custom tailored to address this task, reliable information often is difficult and very time consuming to attain in the vast majority of cases, namely when the molecular conductance is much smaller than $e^2/h$. The article recapitulates procedures for molecular transport calculations from the point of view of time-dependent density functional theory. Emphasis is describing the foundations of the ``standard method''. Pitfalls will be uncovered and the domain of applicability discussed.