Atom-Wide Co Wires on Cu(775) at Room Temperature

TL;DR

This study reports the discovery of stable, self-assembled cobalt quantum wires on a copper surface at room temperature, providing insights into their formation and coexistence with other phases.

Contribution

It introduces a new surface phase with uniform Co wires on Cu(111), observed at room temperature, and compares experimental results with theoretical models.

Findings

Co wires form along step edges at specific coverage levels

Wires increase in length with increased Co coverage

Co wires coexist with a predicted Co phase

Abstract

We report on a new surface phase of the Co-vicinal-Cu(111) system which exhibits self-assembled uniform Co quantum wires that are stable at 300K. STM-imaging measurements show that wires will self-assemble within a narrow range of Co coverage and, within this range, the wires increase in length as coverage is increased. The STM images show that the wires form along the leading edge of the step rise, differentiating it from previously theoretically predicted atomic-wire phases. The formation of relatively long laterally un-encapsulated one- and two-atom wires also differentiates it from past experimentally observed step-island formation. Furthermore, our experiments also show directly that the Co wires coexist with another Co phase that had been previously predicted for growth on Cu(111). Our observations allow us to comment on the formation kinetics of the atomic-wire phase and on the fit of our data to a recently developed lattice-gas model.