Observation of the Smallest Metal Nanotube with Square-cross-section

TL;DR

This paper reports the discovery of the smallest metal nanotube with a square cross-section formed during elongation of silver nanocontacts, highlighting its unique structure and mechanical properties.

Contribution

It introduces the spontaneous formation of the smallest square-cross-section metal nanotube, supported by ab initio and molecular simulations, revealing new nanoscale structural behavior.

Findings

Smallest metal nanotube with square cross-section observed

Nanotube formation minimizes surface energy

Structure absorbs large tensile deformation

Abstract

Understanding the mechanical properties of nanoscale systems requires a range of measurement techniques and theoretical approaches to gather the relevant physical and chemical information. The arrangements of atoms in nanostructures and macroscopic matter can be different, principally due to the role of surface energy, but the interplay between atomic and electronic structure in association with applied mechanical stress can also lead to surprising differences. For example, metastable structures such as suspended chains of atoms and helical wires have been produced by the stretching of metal junctions. Here we report the spontaneous formation of the smallest possible metal nanotube with a square cross-section during the elongation of silver nanocontacts. Ab initio calculations and molecular simulations indicate that the hollow wire forms because this configuration allows the surface energy to be minimized, and also generates a soft structure capable of absorbing a huge tensile deformation.