Experimental and theoretical evidence of image states at semiconductor surfaces: The case of GaP(1 1 0)

The first theoretical and experimental analysis of image states at a semiconductor surface is presented: results of angle resolved inverse photoemission and of ab-initio pseudopotential calculation in the non-local density approximation for GaP(1 1 0) are compared showing the presence of a well defined image state with a dispersion in k-space very different from the one predicted by simple models. © 1990.