Highly Aligned Epitaxial Nanorods with a Checkerboard Pattern in Oxide Films

One of the central challenges of nano-science is fabrication of nano-scale structures with well-controlled architectures using planar thin-film technology. Herein, we report our discovery of a periodic nanometer-scale self-assembly in spinel films, fabricated by manipulating spontaneous phase separation and substrate strain. The films consist of two types of chemically-distinct nanorods with mutually coherent interfaces, perfectly aligned along the film growth direction. This unique three dimensional epitaxy process contrasts with a typical behavior in conventional growth of highly lattice-mismatched films, and thus provides an important route for film fabrication of nano-structured arrays with periodically varied electronic and magnetic properties.