Quasicrystals: Intellectual Beauty and Physical Opportunities
Patricia A. Thiel
and Materials Science & Engineering
Quasicrystals are metallic alloys in which the atoms exhibit a remarkable arrangement: They are well-ordered, but not in a periodic fashion. Even more interesting, these materials exhibit unusual combinations of physical properties--apparently linked to their atomic structure. The opportunity to use these materials as templates for growth is the topic of this talk.
Specifically, we have studied metals deposited on
quasicrystalline substrates in order to derive fundamental physical insights
into the processes and energetics involved in formation of an
aperiodic-periodic interface. In this
talk, I will provide examples of three main types of information, which can be
obtained from different coverage (thickness) regimes. With increasing coverage,
they are: (i) nucleation; (ii) growth modes, reflecting surface and interface
energies; and (iii) crystallographic
orientations—specifically, relationships between high-symmetry zone axes of the
quasicrystal and the thick crystalline film. To derive these types of
information, we have measured film structures of Ag and Al, as probe metals, on
a number of different substrates, including Al(111), the x’ Al-Pd-Mn approximant, the fivefold surface of
icosahedral Al-Pd-Mn, and the tenfold surface of decagonal Al-Ni-
Acknowledgments.
This work was supported by the Director, Office of Science, Office of Basic
Energy Science, Materials Science Division of the US Department of Energy.