Surface electronic structure and screening of3d-band holes in Cu(100)

Analysis of the core-level and valence-band binding-energy shifts at the Cu(100) surface demonstrates that holes in the Cu $3d$ band are screened by $4sp$ electrons as effectively as are deep core holes. The common view of the photoemission final state as simply an itinerant $3d$ hole should be replaced by the concept of a $3d$ hole and its $4sp$ screening charge propagating through the lattice together. It appears that this phenomenon also plays an important role in determining photoemission properties of transition metals.