Spin-resolved unoccupied electronic band structure from quantum size oscillations in the reflectivity of slow electrons from ultrathin ferromagnetic crystals.

The spin-dependent reflectivity of electrons with energies between 0 and 20 eV from Fe single crystals 2-8 monolayers thick on a W(110) surface is studied by spin-polarized low energy electron microscopy. The quantum size oscillations in the reflectivity are analyzed in a similar manner as in photoemission of ground state electrons, yielding the spin-resolved unoccupied state band structure of Fe in the Gamma N direction in the energy range studied.