NONLOCAL SCREENING EFFECTS IN 2P X-RAY PHOTOEMISSION SPECTROSCOPY OF NIO(100)

We report on the layer thickness dependence of Ni 2p core-level line s hapes of epitaxially grown, in a layer-by-layer fashion, NiO on a sing le-crystal MgO (100) substrate. The results demonstrate the sensitivit y of the core-level line shape to the nearest as well as next-nearest- neighbor coordination number. The results are consistent with a recent theoretical study of nonlocal screening effects.