Thickness-dependent electronic transition and emergent edge states in few-layer SmTe(111) films

Two-dimensional rare-earth chalcogenides exhibit promising quantum phenomena for nanoelectronics. We synthesized non-van der Waals samarium telluride (SmTe) films on Ag(111) through ultrahigh vacuum co-deposition and characterized them using scanning tunneling microscopy. Our measurements reveal a thickness-dependent electronic transition from a metallic-like monolayer to a semiconducting bilayer with a bandgap of approximately 0.3 eV. Moreover, we observed an emergent state between ∼0.15 and ∼0.55 eV, localized at the step edge of the second layer with a spatial extent of around 1.9 nm. These results demonstrate a significant thickness-dependent evolution of the electronic structure in this non-van der Waals system, providing important insights for future device applications.