Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 12: Morphology Prediction at Interfaces
O 12.11: Talk
Monday, March 7, 2016, 17:30–17:45, S051
An Interfacial Bridge from a Perovskite to a Fluorite — Marita O’Sullivan1, Joke Hadermann2, •Matthew S Dyer1, Stuart Turner2, Jonathan Alaria1, Troy Manning1, Artem M Abakumov2, John B Claridge1, and Matthew J Rosseinsky1 — 1University of Liverpool, Liverpool, UK — 2EMAT, Univerisity of Antwerp, Antwerp, Belgium
Coherent interfaces between materials are essential for many technological processes, and can give rise to novel physical properties. Such interfaces can be obtained by controlled 2D layer-by-layer growth of one material on another. Dimensional matching on the unit cell length scale can usually used to determine whether 2D layer-by-layer growth is possible when both materials have the same or similar structures, but not when the materials have very different structures. For example, perovskite / fluorite interfaces can be engineered with less than 1 % strain, but 2D layer-by-layer growth still cannot be achieved. Using pulsed laser deposition, we demonstrate 2D layer-by-layer growth of the lattice matched disordered fluorites La0.5Zr0.5O1.75 and Nd0.5Zr0.5O1.75 on the perovskite LaAlO3. A joint DFT and STEM investigation of the interface shows that local restructuring occurs forming a bridge between the perovskite and fluorite, satisfying the local bonding of both structures. The restructuring is made possible by the chemical flexibility of the chosen fluorites. This suggests both dimensional and chemical matching are important for the creation of coherent interfaces between materials with significantly differing structures, and that chemical mismatches can be overcome by a careful choice of materials.