ASYMMETRIC PEAK BROADENING IN PHOTOEMISSION OF SURFACE-STATES AS A CONSEQUENCE OF LATERAL ELECTRON CONFINEMENT

In addition to the inverse lifetime, the photoemission peak width of a surface state depends on the quality of the surface. For a stepped su rface, in particular, there is an energy shift of the surface state ow ing to the confinement of electrons. A random distribution of steps ca uses an asymmetric peak broadening, which is examined as a function of the shift parameter, the inverse lifetime and the mean terrace width. The model is discussed for the Cu(111) sp-surface state for which an influence of steps on the peak shape is obtained particularly for mean terrace widths less than 100 Angstrom. (C) 1997 Elsevier Science B.V.