Kagome-derived epitaxial silverene: Designer atom-thin two-dimensional silver on semiconducting germanium

Crystalline ultra-thin noble metal sheets could play a key role in several advanced nanotechnologies. Here, atom-thin epitaxial silver is synthesized in situ under Ultra-High Vacuum on a semiconducting germanium wafer template upon forming a 6x6-Ag/ Ge(111) nanolattice observed in low energy electron diffraction. In the same UHV experimental set-up, the system is further characterized with photoelectron spectroscopy at 39 K (valence band and core-levels) and next observed in scanning tunneling microscopy at 4.4 K, revealing an ultra-smooth two-dimensional overlayer. Its internal structure is determined by way of thorough density functional theory calculations and image simulations, which point to a unique Kagome-derived atomic geometry, an unprecedented form of twodimensional silver: epitaxial silverene.