Chemical Bonding and Charge Distribution at Metallic Nanocontacts

TL;DR

This study uses density functional theory to analyze atomic-scale aluminium nanocontacts, revealing significant deviations in electronic structure and charge distribution from bulk aluminium, impacting transport property models.

Contribution

It provides detailed electronic structure insights at metallic nanocontacts, highlighting deviations from bulk behavior and implications for transport models.

Findings

Suppressed hybridization between Al 3s and 3p states at the contact

Charge transfer of 0.6 electrons off the aluminium site

Local band structure differs markedly from bulk aluminium

Abstract

We present results of electronic structure calculations for aluminium contacts of atomic size, based on density functional theory and the local density approximation. Addressing the atomic orbitals at the neck of the nanocontact, we find that the local band structure deviates strongly from bulk fcc aluminium. In particular, hybridization between Al 3s and 3p states is fully suppressed due to directed bonds at the contact. Moreover, a charge transfer of 0.6 electrons off the contact aluminium site is found. Both the suppressed hybridization and the violated charge neutrality are characteristic features of metallic nanocontacts. This fact has serious consequences for models aiming at a microscopic description of transport properties.