Structural evolution of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si284.svg" display="inline" id="d1e1751"> <mml:mi>γ</mml:mi> </mml:math> -antimonene nanoribbons on Ag(110)

We report on the structural and chemical evolution of antimony (Sb) monolayer on Ag(110). At a coverage of 0.5 ML, Sb forms a substitutional c ( 2 × 2 ) alloy, as determined by our LEED-IV (Low-Energy Electron Diffraction) analysis. For a higher coverage above 0.5 ML, γ -like Sb nanoribbons grow along the [ 001 ] direction. The γ -Sb phase has not yet been reported experimentally. Atomically resolved Scanning Tunneling Microscopy (STM) measurements reveal two distinct ribbon types that are stochastically distributed across the surface. We report a coverage-dependent spot splitting in Low-Energy Electron Diffraction (LEED), arising from this stochastic arrangement. In contrast to a previous report suggesting ribbon growth atop the alloy, our angle-resolved X-ray Photoelectron Spectroscopy (XPS) measurements show that the alloy becomes less significant as ribbon formation proceeds. Until now, detailed chemical investigations such as XPS have been missing; we fill this gap by performing high-resolution XPS measurements, revealing the internal and interfacial composition of the Sb/Ag(110) system. Furthermore, our XPS analysis reveals that the Sb atoms inside the γ -like Sb ribbons have two distinct chemical environments; an interface layer and an upper ribbon layer. Based on these results, we can refute the previous structural model Wang et al. (2022) and propose Sb ribbons growing in the γ -Sb configuration. • Epitaxial growth of narrow and wide Sb nanoribbons on Ag(110). • First evidence of γ -Sb nanoribbons by XPS and STM. • Spot-splitting in LEED due to stochastic distribution of narrow and wide ribbons. • Antimony coverage determines nanoribbon width.