H$_2$ dissociation over Au-nanowires and the fractional conductance quantum

TL;DR

This study combines DFT and Keldish-Green methods to analyze how stretched Au nanowires catalyze H$_2$ dissociation and how this affects their conductance, revealing fractional conductance states induced by atomic hydrogen.

Contribution

It demonstrates that stretched Au nanowires are more effective catalysts for H$_2$ dissociation and links this to observable fractional conductance phenomena.

Findings

Au nanowires form monoatomic chains with conductance near $G_0$

Nanowires catalyze H$_2$ dissociation more effectively than surfaces

Atomic hydrogen causes fractional conductance around 0.5 $G_0$

Abstract

The dissociation of H$_2$ molecules on stretched Au nanowires and its effect on the nanowire conductance are analyzed using a combination of Density Functional (DFT) total energy calculations and non-equilibrium Keldish-Green function methods. Our DFT simulations reproduce the characteristic formation of Au monoatomic chains with a conductance close to % the conductance quantum $G_0 = 2e^2/h$. These stretched Au nanowires are shown to be better catalysts for H$_2$ dissociation than Au surfaces. This is confirmed by the nanowire conductance evidence: while not affected practically by molecular hydrogen, atomic hydrogen induces the appearance of fractional conductances ($G \sim 0.5 G_0$) as observed experimentally.