Surface studies using spin-polarized ion neutralization spectroscopy
Kontur, Frederick J.
Dunning, F. B.
Master of Science
Spin-polarized ion neutralization spectroscopy (SPINS), in which a beam of electron-spin-polarized He+ ions is directed onto a surface and analysis is done of the electrons ejected from the surface as a result of ion neutralization, is a unique tool for surface studies that has unparalleled surface specificity. Using SPINS, we have discovered that the polarization of electrons ejected from Au(100) and Cu(100) is strongly correlated with incident ion polarization. The incident ion, in essence, locally magnetizes the surface, creating a net polarization in the local occupied density of states on the surface. Recent experiments on a CO2-covered surface are also described. The results from these experiments cannot be explained using the traditional Auger or Penning processes. A model is proposed in which the He+ forms a collision complex with one or more CO 2 molecules in the surface layer, making it energetically possible for an electron to be ejected.
Condensed matter physics; Atomic physics