Low-energy electron diffraction and scanning tunneling microscopy studies of FeO(111) films on Ru(0001) show formation of coincidence structures with a Moiré pattern up to a thickness of four monolayers. In the four monolayer thick film, strained conducting ${\mathrm{Fe}}_3{\mathrm{O}}_4\mathrm{}\left(111\right)\mathrm{}$ nanodomains nucleate in the insulating FeO(111) matrix and form an ordered inverse biphase superstructure. Further oxidation causes these domains to grow and to coalesce into a closed ${\mathrm{Fe}}_3{\mathrm{O}}_4\mathrm{}\left(111\right)\mathrm{}$ film.

• Received 12 April 2002

DOI:https://doi.org/10.1103/PhysRevB.66.033405