Gold diggers: Altered reconstruction of the gold surface by physisorbed aromatic oligomers

Abstract

We present electronic structure theory calculations and scanning tunneling microscopy experiments for the adsorption of $\ensuremath{\alpha}$-sexithiophene on the 100 surface of gold. Our density-functional theory calculations show that $\ensuremath{\alpha}$-sexithiophene prefers to adjust an energetically unfavorable adsorption site by modifying the gold surface over seeking out more favorable adsorption sites. Molecular adsorption results in a complex charge transfer pattern, with more charge transfer in more stable sites. Our results challenge the current paradigm that weakly interacting (e.g., physisorbed) molecules perceive metal surfaces as rigid templates with preordained adsorption sites.