  Spin- and angle-resolved resonant (Ce $4d\to4f$) photoemission spectra of a
monolayer Ce on Fe(110) reveal spin-dependent changes of the Fermi-level peak
intensities. That indicate a spin-dependence of $4f$ hybridization and, thus,
of $4f$ occupancy and local moment. The phenomenon is described in the
framework of the periodic Anderson model by $4f$ electron hopping into the
exchange split Fe 3d derived bands that form a spin-gap at the Fermi energy
around the $\bar{\Gamma}$ point of the surface Brillouin zone.
