Electronic structure of the Au/benzene-1,4-dithiol/Au transport interface: Effects of chemical bonding

TL;DR

This study uses density functional theory to analyze the electronic structure of Au/benzene-1,4-dithiol/Au contacts, revealing how chemical bonding influences conductance by affecting electronic states near the Fermi level.

Contribution

It provides detailed insights into the electronic states and hybridization effects at the molecular interface, linking chemical bonding to conductance reduction.

Findings

Au 5d and S 3p states dominate near Fermi energy

C 2p contributions are minimal due to S-C bonding

Reduced conductance aligns with experimental observations

Abstract

We present results of electronic structure calculations for well-relaxed Au/benzene-1,4-dithiol/Au molecular contacts, based on density functional theory and the generalized gradient approximation. Electronic states in the vicinity of the Fermi energy are mainly of Au 5d and S 3p symmetry, whereas contributions of C 2p states are very small. Hybridization between C 2p orbitals within the benzene substructure is strongly suppressed due to S-C bonding. In agreement with experimental findings, this corresponds to a significantly reduced conductance of the molecular contact.