Structural transitions on Si(1 1 1) surface during Sn adsorption, electromigration, and desorption studied by in situ UHV REM

•Sn-induced structural transitions on Si(111) at 200–860 °C have been first visualized.•γ-√3-Sn reconstruction formation atT > 650 °C induces step shift.•Sn surface electromigration entails √3-Sn⇔“1 × 1”-Sn phase transitions.•Sn adatoms have a positive effective charge being ≥ 0.001∙e.•Activation energy of Sn atom desorption from “1 × 1”-Sn layer is 2.5 ± 0.1 eV.