THE ELECTRONIC-PROPERTIES OF THE CAF2-SI(111) SYSTEM - FROM MONOLAYER COVERAGE TO SOLID SOLID INTERFACE

The surface linear muffin-tin method in the atomic-sphere approximation (SLMTO-ASA) is applied to study the electronic properties of the CaF2-Si(111) interface. We investigate the growth of CaF2 on Si(111) following the interface formation from low to high coverages. The early stages of the growth are simulated by an interface formed by a monolayer of Ca deposited on Si(111) followed by a F layer, i.e., a F-Ca-Si(111) system. Both valence- and core-electron states have been calculated. Their analysis gives important information about the nature of the Ca-Si and Ca-F bonds. We explore the dependence of the electronic properties on the number of deposited layers showing that the main contribution to the interface properties is established at monolayer coverage and that the transfer of charge between the two crystals is localized in their last layers.