  Based on measurements of angle resolved photoemission, we report that in the
Pb/Ge(111)- \sqrt{3}x\sqrt{3} R30^\circ structure, in addition to three bands
resembling Ge heavy hole (HH), light hole (LH), and split off (SO) bulk band
edges, a fourth dispersive band resembling the non split off (NSO) band is
found near the surface zone center. While three Ge bulk-like bands get
distorted due to strong coupling between Pb and Ge, the NSO-like band gets
weaker and disappears for larger thickness of Pb, which, when combined with ab
initio calculations, indicates its localized nature within space charge layer.
Our results are clearly important for designing electronics involved with
metal-semiconductor contacts.

Materials Science