Structure of germanene/Al(111): a two-layers surface alloy

Abstract

Unlike silicene, for which the demonstration of its existence has been done through numerous independent studies, the possibility of growing epitaxial germanene remains highly controversial. It has been recently shown by scanning tunneling microscopy that the (3 x 3) surface reconstruction formed upon Ge deposition on Al(111) presents a honeycomb structure, and it was assigned to a pure germanene monolayer. Using quantitative measurements by surface X-ray diffraction compared to density functional theory calculations, we demonstrate that this Ge/Al(111) (3 x 3) reconstruction corresponds, in fact, to a mixed Ge--Al honeycomb layer on top of an alloyed interfacial layer. The model of a germanene monolayer on top of the Al(111) surface can be completely excluded.

References in corpus (5)

• Two and one-dimensional honeycomb structures of silicon and germanium
• Quantum Spin Hall Effect in Silicene
• Germanene termination of Ge${}_2$Pt crystals on Ge(110)
• Coexistence of strongly buckled germanene phases on Al(111)
• Growth of germanium-silver surface alloys followed by in situ scanning tunneling microscopy: Absence of germanene formation