Surface crystallography and epitaxy. Fe thin films are grown on a single-crystal Al(100) substrate surface. The films grow with no dislocations (if they are thin enough) with suggests that the atoms find a way to line up nicely across the Al/Fe interface. Fe is bcc with a lattice parameter of 2.867Å and Aluminum is fcc with a lattice parameter of 4.050 Å. Describe the crystalline orientation of the Fe on the Al(100) surface. (Either draw a picture or tell me which Fe surface is parallel to the Al(100) surface and what direction in the Fe is parallel to what direction in the Al. This problem is rigged to make it very easy. Look at the ratio of the lattice constants and see if it is a familiar number.)