Silicene’s pervasive surface alloy on Ag(111)

David Duncan

Diamond Light Source, Beamline i09
United Kingdom

Wednesday, 25th January 2023,16:00 s.t.

The talk will be given in hybrid mode.

You can either attend in physical presence:
TU Wien, Institute of Applied Physics,
Wiedner Hauptstraße 8-10, 1040 Vienna,
Meeting Room 5C (5th floor, red tower)

Or you join via Zoom:
Meeting ID: 977 8213 7552  Passcode: R9tTYkgX

Silicene’s pervasive surface alloy on Ag(111)

Silicene is the two-dimensional (2D) allotrope of silicon. So far, the most direct synthesis strategy has been to grow it epitaxially on metal surfaces; however, the effect of the strong silicon-metal interaction on the structure and electronic properties of the metal-supported silicene is generally poorly understood. Here, we consider the (4 × 4)-silicene monolayer (ML) grown on Ag(111), and show that our experimental results refute the common interpretation of this system as a simple  buckled, honeycomb ML with a sharp interface to the Ag substrate. Instead, we demonstrate the pervasive presence of a second silicon species, concluded to be a Si/Ag alloy stacked between the 2D silicene and the silver substrate. These findings question the current structural understanding of the silicene/Ag(111) interface and may raise expectations of analogous alloy systems in the stabilization of other 2D materials grown epitaxially on metal surfaces.