Surface shifts in the In 4dand P 2pcore-level spectra of InP(110)

Surface binding energy shifts of the In 4d and P 2p on the InP(110) surface are evaluated from the core-level photoemission spectra. For In 4d we observe a surface peak shifted by 0.3 eV to higher binding energy relative to its bulk counterpart. We were, however, unable to resolve a shift in P 2p and tentatively argue that its value is very small. These results agree with a recent theoretical tight-binding calculation of the surface core-level shifts.