We show that linear polarized x-ray-absorption spectroscopy can be used to measure the temperature and thickness dependence of magnetic moments in NiO thin films. We demonstrate that both the long-range order and the nearest-neighbor spin-spin correlations can be revealed. NiO (100) films with thicknesses of 5, 10, and 20 monolayers epitaxially grown on MgO (100) are studied. The Neel temperature is found to be strongly reduced from the bulk value even for the 20 monolayer film

Angle-resolved photoemission spectroscopy reveals the presence of a two-dimensional electron gas at the surface of In(2)O(3)(111). Quantized subband states arise within a confining potential well associated with surface electron accumulation. Coupled Poisson-Schrödinger calculations suggest that downward band bending for the conduction band must be much bigger than band bending in the valence band. Surface oxygen vacancies acting as doubly ionized shallow donors are shown to provide the free electrons within this accumulation layer. Identification of the origin of electron accumulation in transparent conducting oxides has significant implications in the realization of devices based on these compounds.

The mechanism of secondary electron emission by impact of 100-eV electrons on an Al(100) surface has been investigated by measuring the secondary electron spectrum in coincidence with loss features in the spectrum of reflected electrons. Distinct peaks are observed at energies corresponding accurately to the surface and bulk plasmon energies minus the work function of the analyzer, demonstrating that plasmons excited by electron energy losses predominantly decay via creation of single-electron-hole pairs that act as a source for the secondary electron spectrum. These findings suggest a mechanism for emission of secondary electrons very similar to photoelectron (PE) emission, the difference being the step leading to electron liberation, i.e., plasmon decay in the present case versus photoionization in the case of PE

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