Determination of the coincidence lattice of an ultra thin Al2O3 film on Ni3Al(1Â 1Â 1)

Spot profile analysis low energy electron diffraction (SPA-LEED) and low temperature scanning tunneling microscopy (LT-STM) measurements were performed on an ultra thin alumina film grown at 1000 K in an oxygen atmosphere on Ni3Al(1 1 1). By the aid of these two experimental techniques it has been shown that the alumina film exhibits a large superstructure with a lattice constant of 4.16 nm. The unit cell of this superstructure has a commensurate (√67 × √67)R47.784° relation to the Ni3Al(1 1 1) substrate lattice.