Structural investigation of flat overlayer and surface alloy of Sn on Mo(110)

Abstract

Atomic structures of Sn on Mo(110) are investigated using low-energy electron diffraction (LEED) and density functional theory (DFT) calculation. Sn atoms occupy substitutional sites at elevated temperatures in (3 × 1) structure, corresponding to a coverage of 0.33 ML. The substitutional model agrees with previous LEED, workfunction, and STM results. For (1 × 3) structure at 0.67 ML, Sn atoms adsorb in the nearest three-fold hollow sites. With increasing Sn coverage, the (1 × 4) structure at 0.75 ML, Sn atoms start to fill four-fold hollow sites. On both overlayer phases, Sn structures are flat without significant buckling. Compared with a two-dimensional tin, stanene, which is a stacking of α-Sn(111), Sn overlayer on Mo(110) is not related to α-Sn(111) but to β-Sn(100), which is normal metallic