Electronic structure and bonding at the Al–terminated Al(111)/ –Al2O3(0001) interface: A first principles study

We have performed ab initio calculations to determine the bonding character of the Al–terminated Al(111)/ –Al2O3(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.