Electronic properties of lithium

Gavin McKay Watson, University of Pennsylvania


The electronic properties of Li films grown on Be(0001) are studied using angle-resolved photoemission, inverse photoemission, and electron energy loss spectroscopy. The bulk bandstructure of Li is measured along the $\Gamma$ to N axis of the bulk Brillouin zone. The dispersion of the initial state with photon energy is found to be non-parabolic and is explained in terms of final state effects. An occupied bandwidth of 2.86 eV is measured and compared to self-energy calculations. A systematic discrepancy between calculated and measured quasiparticle widths is identified and discussed. The surface plasmon for thick films is measured and a negative dispersion is found for small momentum transfers. At q$\sb\Vert$ = 0, the measured surface plasmon energy and width are compared to the surface loss function using the measured optical properties of Li. No multipole mode is observed in the electron energy loss spectroscopy measurements. The electronic states for Li films in the submonolayer and monolayer regime are measured as a function of coverage. In the sub-monolayer range, the transition to a metallic state, where the overlayer band is partially occupied, is found to be abrupt rather than continuous. This transition coincides with a change the screening in the overlayer as illustrated by a shift in the Li 1s binding energy and vibrational electron energy loss measurements. The first clear picture of the bandstructure for a single, close-packed, alkali overlayer on a metal is found. The overlayer band is shown to be metallic. Interactions of the Li band with the substrate states are illustrated, including an avoided band crossing.

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Recommended Citation

Watson, Gavin McKay, "Electronic properties of lithium" (1993). Dissertations available from ProQuest. AAI9321498.