Vibronic effects in single molecule conductance: First-principles description and application to benezenealkanethiolates between gold electrodes

TL;DR

This paper investigates how vibrational motions influence charge transport in single molecule junctions, using first-principles calculations and inelastic scattering theory, with a focus on benzene-alkanethiolate molecules connected to gold electrodes.

Contribution

It introduces a combined first-principles and inelastic scattering methodology to analyze vibronic effects in molecular conductance, including hole transport through molecular orbitals.

Findings

Vibronic coupling significantly affects transport depending on electronic coupling strength.

The methodology extends to describe hole transport through occupied orbitals.

Vibrational effects can alter conductance in benzene-based molecular junctions.

Abstract

The effect of vibrational motion on resonant charge transport through single molecule junctions is investigated. The study is based on a combination of first-principles electronic structure calculations to characterize the system and inelastic scattering theory to calculate transport properties. The extension of the methodology to describe hole transport through occupied molecular orbitals is discussed. The methodology is applied to molecular junctions where a benzene molecule is connected via alkanethiolate bridges to two gold electrodes. The results demonstrate that, depending on the coupling between the electronic $\pi$-system of the benzene ring and the gold electrodes, vibronic coupling may have a significant influence on the transport properties of the molecular junction.