Probing depths of low energy electrons in metals

[摘要] Spin-polarized electron energy-loss spectroscopy has been used to investigate the probing depth of low energy ($sim$30 eV) electrons in metals. A beam of spin-polarized electrons is directed at the surface of the sample and the polarization of the scattered electrons is measured as the function of inelastic energy loss. Different polarization loss features were observed from Cu(100) and Mo(110). By depositing thin molybdenum (copper) films on a Cu(100) (Mo(110)) substrate and observing the appearance (disappearance) of the molybdenum polarization loss feature, it is found that the probing depth in molybdenum is small ($sim$1 monolayer), but is significantly larger in copper ($sim$3 monolayers). This difference can be explained by the differences of the joint density of states available for electron-hole pair excitation. The growth mode of Fe/Cu(100) has also been studied by using this method.

[发布机构] Rice University