Quasicrystalline Oxides

Two years after the 2011 Nobel Prize in Chemistry was awarded for the discovery of quasicrystals, this class of unusually ordered materials remains relatively obscure. Unlike conventional crystals, quasicrystals lack periodicity, meaning their atomic structures do not repeat in three dimensions at fixed intervals. Most quasicrystals, some of which are used to harden steel and endow high-end cookware with stick- and scratch-resistance, are metals and are prepared via a small number of alloying methods. Stefan Förster, Wolf Widdra, and coworkers at Martin Luther University of Halle-Wittenberg, in Germany, have demonstrated a new way to make quasicrystals and used the method to make a quasicrystalline oxide film (Nature 2013, DOI: 10.1038/nature12514). After growing a crystalline film of BaTiO₃ on platinum via conventional methods, the team heated the material in vacuum. On the basis of electron diffraction and microscopy analysis, they conclude that the heat treatment and BaTiO₃/platinum interfacial energy drive the oxide to adopt a quasicrystalline structure. The method, which had not been expected to yield oxide quasicrystals, might lead to other oxide quasicrystals with unexpected properties, Widdra says.