Electronic structure effects in stability and quantum conductance in 2D gold nanowires

TL;DR

This study uses ab-initio DFT to analyze the stability and quantum conductance of 2D gold nanowires, revealing structural preferences, electronic delocalization, and conductance properties relevant for nanoscale electronics.

Contribution

It provides a comprehensive analysis of the stability and electronic properties of unsupported 2D gold nanowires with various structures, highlighting the role of atomic arrangement and orientation.

Findings

Parallelogram motif is most stable in 2D gold nanowires.

(111) oriented nanowires are more stable than (100) ones.

Most nanowires are metallic and conductive, except double zigzag structures.

Abstract

We have investigated the stability and conductivity of unsupported, two dimensional infinite gold nanowires using ab-initio density functional theory (DFT). Two dimensional ribbon like nanowires, with 1-5 rows of gold atoms in the non-periodic direction and with different possible structures have been considered. The nanowires with > 2 rows of atoms exhibit dimerization, similar to finite wires, along the non-periodic direction. Our results show that in these zero thickness nanowires, the parallelogram motif is the most stable. A comparison between parallelogram and rectangular shaped nanowires of increasing width indicates that zero thickness (111) oriented wires have a higher stability over (100). A detailed analysis of the electronic structure, reveals that the (111) oriented structures show increased delocalization of s and p electrons in addition to a stronger delocalization of the d electrons and hence are the most stable. The density of states show that the nanowires are metallic and conducting except for the double zigzag structure, which, is semiconducting. Conductance calculations show transmission for a wide range of energies in all the stable nanowires with more than two rows of atoms. The conductance channels are not purely s and have strong contributions from the d levels and weak contributions from the p levels.