Interaction of a CO molecule with a Pt monoatomic chain: the top geometry

TL;DR

This study uses DFT calculations to analyze how CO adsorption affects the electronic structure and conductance of a platinum monoatomic chain, revealing a moderate conductance reduction and detailed interaction mechanisms.

Contribution

It provides a detailed theoretical analysis of CO adsorption effects on Pt atomic chains, including electronic interactions and conductance changes, with and without spin-orbit coupling.

Findings

Conductance decreases from 4 G_0 to 3.1 G_0 upon CO adsorption.

Main electronic interactions involve donation/back-donation via specific orbitals.

Spin-orbit coupling has negligible effect on interaction and conductance.

Abstract

Recent experiments showed that the conductance of Pt nanocontacts and nanowires is measurably reduced by adsorption of CO. We present DFT calculations of the electronic structure and ballistic conductance of a Pt monoatomic chain and a CO molecule adsorbed in an on-top position. We find that the main electronic molecule-chain interaction occurs via the $5\sigma$ and $2\pi^{\star}$ orbitals of the molecule, involved in a donation/back-donation process similar to that of CO on transition-metal surfaces. The ideal ballistic conductance of the monoatomic chain undergoes a moderate reduction by about 1.0 G_0 (from 4 G_0 to 3.1 G_0) upon adsorption of CO. By repeating all calculations with and without spin-orbit coupling, no substantial spin-orbit induced change emerges either in the chain-molecule interaction mechanism or in the conductance.