Ag-coverage-dependent symmetry of the electronic states of the Pt(111)-Ag-Bi interface: The ARPES view of a structural transition

TL;DR

This study uses ARPES to investigate how the symmetry of electronic states at the Pt(111)-Ag-Bi interface varies with Ag coverage, revealing a coverage-dependent structural transition from pseudomorphic to striped phases.

Contribution

It provides the first detailed ARPES analysis of the symmetry changes in interface states related to the Ag coverage-dependent structural transition.

Findings

Symmetry of Bi-derived interface states changes from threefold to sixfold and back to threefold.

Coverage-dependent structural transition is confirmed by ARPES and microscopy data.

Provides microscopic insight into the Ag film's structural evolution on Pt(111).

Abstract

We studied by angle-resolved photoelectron spectroscopy the strain-related structural transition from a pseudomorphic monolayer (ML) to a striped incommensurate phase in an Ag thin film grown on Pt(111). We exploited the surfactant properties of Bi to grow ordered Pt(111)-xMLAg-Bi trilayers with 0 < x < 5 ML, and monitored the dispersion of the Bi-derived interface states to probe the structure of the underlying Ag film. We find that their symmetry changes from threefold to sixfold and back to threefold in the Ag coverage range studied. Together with previous scanning tunneling microscopy and photoelectron diffraction data, these results provide a consistent microscopic description of the coverage-dependent structural transition.