Surfactant-mediated growth of epitaxial films on quasiperiodic surfaces

We have succeeded for the first time in inducing epitaxial growth of metal films on quasiperiodic surfaces. Depositions of Au onto the tenfold surface of a decagonal Al-Ni-Co quasicrystal were originally attempted to create a quasicrystal of a single element as an epitaxial film. Although the desired film was not obtained on the clean surface, a multiply twinned AuAl₂ crystalline layer with a (110)-oriented surface was formed with the aid of an In pre-deposition layer. The presence of pre-deposited In also worked as a surfactant for the case of Au-deposition onto the fivefold surface of an icosahedral Al-Pd-Mn quasicrystal and promoted the formation of an ordered film of Au-Al alloy. X-ray photoelectron diffraction images from this ordered film show that the alloy has an icosahedral structure as a long range order, suggesting the formation of a quasicrystalline film.