Evolution of unoccupied resonance during the synthesis of a silver dimer on Ag(111)

TL;DR

This study investigates how unoccupied electronic resonances in silver dimers on Ag(111) shift during synthesis, revealing direct atom-atom coupling effects through combined experimental and computational analysis.

Contribution

It provides new insights into the evolution of unoccupied resonances during silver dimer formation, highlighting the dominance of direct coupling over substrate-mediated interactions.

Findings

Resonance shifts toward Fermi level with decreasing atom distance

Direct atom-atom coupling dominates over substrate-mediated interactions

Experimental observations are supported by density functional calculations

Abstract

Silver dimers were fabricated on Ag(111) by single-atom manipulation using the tip of a cryogenic scanning tunnelling microscope. An unoccupied electronic resonance was observed to shift toward the Fermi level with decreasing atom-atom distance as monitored by spatially resolved scanning tunnelling spectroscopy. Density functional calculations were used to analyse the experimental observations and revealed that the coupling between the adsorbed atoms is predominantly direct rather than indirect via the Ag(111) substrate.