An atomistic view of structural and electronic properties of rare earth ensembles on Si(0 0 1) substrates

Synergistic experimental and theoretical studies of low coverage adsorption geometries of rare earth adatoms on Si(0 0 1) were performed. Density functional calculations showed charge transfer from adatoms to Si(0 0 1) and explained observed bias dependence in scanning tunneling microscopy images. Comparison of STM simulations with empty states STM data revealed a direct correlation between coverage and surface reconstructions; the (4 × 8) reconstruction is a low coverage precursor to (2 × 4) reconstruction. Charge transfer from adatom to substrate was also confirmed by Kelvin probe force microscopy; contact potential difference measurements of Dy/Si(0 0 1) reveal a 0.28 eV higher surface potential than that of (2 × 1) reconstructed Si.