# Geometry Effects at Atomic-Size Aluminium Contacts

## TL;DR

This paper investigates how atomic-scale geometry influences electronic states and transport properties in aluminium nanocontacts, revealing sensitivity of Al 3pz states and effects of mechanical stress on charge transfer.

## Contribution

It provides detailed electronic structure calculations showing the impact of local geometry and mechanical stress on aluminium nanocontacts, highlighting the sensitivity of specific orbitals.

## Key findings

- Al 3pz states are highly sensitive to orbital overlap modifications.
- Stretching shifts states towards the Fermi energy, risking ferromagnetic instability.
- Mechanical stress affects charge transfer and local hybridization.

## Abstract

We present electronic structure calculations for aluminium nanocontacts. Addressing the neck of the contact, we compare characteristic geometries to investigate the effects of the local aluminium coordination on the electronic states. We find that the Al 3pz states are very sensitive against modifications of the orbital overlap, which has serious consequences for the transport properties. Stretching of the contact shifts states towards the Fermi energy, leaving the system instable against ferromagnetic ordering. By spacial restriction, hybridization is locally suppressed at nanocontacts and the charge neutrality is violated. We discuss the influence of mechanical stress by means of quantitative results for the charge transfer.