Silicene on Ag(111): an honeycomb lattice without Dirac bands

TL;DR

This study uses experimental and theoretical methods to show that silicene on Ag(111) does not preserve Dirac fermion properties, as interface states dominate the spectral features instead of silicene's intrinsic bands.

Contribution

It provides evidence that silicene's Dirac bands are suppressed on Ag(111), clarifying the nature of electronic states in silicene-metal interfaces.

Findings

Dirac cones are absent in silicene on Ag(111)

Interface states of Ag origin dominate spectral features

Silicene's { extpi}-symmetry states lose local character

Abstract

The discovery of (4x4) silicene formation on Ag(111) raised the question on whether silicene maintains its Dirac fermion character, similar to graphene, on a supporting substrate. Previous photoemission studies indicated that the {\pi}-band forms Dirac cones near the Fermi energy, while theoretical investigations found it shifted at deeper binding energy. By means of angle-resolved photoemission spectroscopy and density functional theory calculations we show instead that the {\pi}-symmetry states lose their local character and the Dirac cone fades out. The formation of an interface state of free-electron-like Ag origin is found to account for spectral features that were theoretically and experimentally attributed to silicene bands of {\pi}-character.