%0 Journal Article
%A Warusawithana, M. P.
%A Richter, C.
%A Mundy, J. A.
%A Roy, P.
%A Ludwig, J.
%A Paetel, S.
%A Heeg, T.
%A Pawlicki, A. A.
%A Kourkoutis, L. F.
%A Zheng, M.
%A Lee, M.
%A Mulcahy, B.
%A Zander, Willi
%A Zhu, Y.
%A Schubert, Jürgen
%A Eckstein, J. N.
%A Muller, D. A.
%A Hellberg, C. Stephen
%A Mannhart, J.
%A Schlom, D. G.
%T LaAlO3 stoichiometry is key to electron liquid formation at LaAlO3/SrTiO3 interfaces
%J Nature Communications
%V 4
%@ 2041-1723
%C London
%I Nature Publishing Group
%M FZJ-2013-03754
%P 9
%D 2013
%X Emergent phenomena, including superconductivity and magnetism, found in the two-dimensional electron liquid (2-DEL) at the interface between the insulators lanthanum aluminate (LaAlO3) and strontium titanate (SrTiO3) distinguish this rich system from conventional 2D electron gases at compound semiconductor interfaces. The origin of this 2-DEL, however, is highly debated, with focus on the role of defects in the SrTiO3, while the LaAlO3 has been assumed perfect. Here we demonstrate, through experiments and first-principle calculations, that the cation stoichiometry of the nominal LaAlO3 layer is key to 2-DEL formation: only Al-rich LaAlO3 results in a 2-DEL. Although extrinsic defects, including oxygen deficiency, are known to render LaAlO3/SrTiO3 samples conducting, our results show that in the absence of such extrinsic defects an interface 2-DEL can form. Its origin is consistent with an intrinsic electronic reconstruction occurring to counteract a polarization catastrophe. This work provides insight for identifying other interfaces where emergent behaviours await discovery.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000323753200012
%$ pmid:23965846
%R 10.1038/ncomms3351
%U https://juser.fz-juelich.de/record/137299