Asymmetric coherent tilt boundaries formed by molecular beam epitaxy

The authors describe a novel system in which low-angle, asymmetric tilt boundaries organise spontaneously under conditions of molecular beam epitaxial growth. In the cases studied, the (1012) surfaces of hexagonal rare earths grow coherently but tilted on the (211) surfaces of BCC transition metals. The main driving forces are interfacial coherency and the relief of long-range epitaxial strain.