Gold Atoms Promote Macroscopic Superconductivity in an Atomic Monolayer of Pb on Si(111)

Atomically thin superconductivity in Pb monolayers grown on Si(111) is affected by adding a tiny amount of Au atoms. In situ macroscopic electron transport measurements reveal that superconductivity develops at higher temperatures and manifests a sharper superconducting transition to zero resistance as compared to pristine Pb/Si(111). Scanning tunneling microscopy and spectroscopy show that Au atoms decorate atomic step edges of Pb/Si(111) and link the electronic reservoirs of neighboring atomic terraces. The propagation of superconducting correlations across the edges is enhanced, facilitating the coherence between terraces and promoting macroscopic superconductivity at higher temperatures. This finding opens new ways to design and control Josephson junctions at the atomic scale.

Automated summary

Atomically thin superconductivity in Pb monolayers grown on Si(111) is affected by the addition of a small amount of Au atoms, which decorate the atomic step edges of Pb/Si(111) and link the electronic reservoirs of neighboring atomic terraces. This enhances the propagation of superconducting correlations across edges, facilitating coherence between terraces and promoting macroscopic superconductivity at higher temperatures.