CORE-LEVEL ANALYSIS OF THE K GAP(110) INTERFACE/

The results of a photoelectron spectroscopy study of the K/GaP(110) in terface grown at T=120 K are presented for the first time. The analysi s shows a big core level shift at lower binding energies (Delta E=1.6 eV at a coverage theta=0.1 ML) for the P 2p core level spectra. We int erpret this result in terms of a charge redistribution affecting both types of atoms of the first substrate layer, suggesting some differenc es from the intuitive picture of strong ionic localised bonding betwee n the alkali and the surface Ga atom.