Self-organized layered structure in epitaxially stabilized FeSi

Conversion electron Mössbauer spectroscopy and transmission electron microscopy investigations of epitaxially stabilized c-FeSi having the CsCl structure reveal a self-organized layered structure. Upon annealing the structural phase transition to the bulk stable ∈-FeSi phase leaves the superlattice periodicity intact with surprisingly sharp interfaces. A distorted CsCl phase which tranforms into the ∈-FeSi phase at a temperature slightly higher than that for the partially relaxed c-FeSi is identified in the as-grown sample. Molecular-dynamics simulations have been used to visualize and interpret the distorted phase and the structural phase transition.