Electronic Structure and Bonding At the

We have performed ab initio calculations to determine the bonding character of the Al--terminated Al(111)/#--Al 2 O 3 (0001) interface. By using an optimized model in which all atomic coordinates were relaxed to their minimum energy positions, we have determined that Al--O bonds constitute the primary interfacial bonding interaction. Our electron localization, Mayer bond order, and Mulliken population analyses reveal that these bonds are very similar to the cation--anion bonds found in the bulk oxide, and are therefore mainly ionic, with a smaller amount of covalent character. However, there is also evidence of metal--cation bonding across the interface, a result which could be significant to understanding bonding at interfaces with other corundum-like oxides