The recent years have seen
the discovery of various exotic phenomena at complex oxide interfaces, which
are expected to revolutionize various technological applications in
electronics, spintronics and data-storage. Combined with their unique
(multi-)functional properties, complex oxide heterostructures display some of
the most chemically abrupt, atomically precise interfaces, which is
advantageous when constructing new interface phases with emergent properties by
juxtaposing incompatible ground states. One might
assume that atomically precise interfaces result from stoichiometric growth. In
a publication appearing in Nature Communications, we show that the most
precise control is obtained utilizing deliberate and specific
non-stoichiometric growth conditions. For the precise growth of Srn+1TinO3n+1
Ruddlesden-Popper (RP) phases, stoichiometric deposition leads to the loss of
the first RP rock-salt double layer, but growing with a strontium-rich surface
layer restores the bulk stoichiometry and ordering of the subsurface RP
structure. These results dramatically expand the materials that can be prepared
in epitaxial heterostructures with precise interface control – from just the n
= 1 end members (perovskites) to the entire RP homologous series - enabling the
exploration of novel quantum phenomena at a richer variety of oxide interfaces.
(Figure : courtesy of Y. F. Nie)
Atomically precise interfaces from non-stoichiometric deposition, Y.
F. Nie, Y. Zhu, C.-H. Lee, L. F. Kourkoutis, J. A. Mundy, J. Junquera, Ph.
Ghosez, D. J. Baek, S. H. Sung, X. X. Xi, K. M. Shen, D. A. Muller, and D. G. Schlom,
Nature Communications 5, 4530 (2014) [DOI: 10.1038/ncomms5530]
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News and Views “Oxide heterostructures: Atoms on the move” by Guus Rijnders