TY  - JOUR
AU  - Warusawithana, M. P.
AU  - Richter, C.
AU  - Mundy, J. A.
AU  - Roy, P.
AU  - Ludwig, J.
AU  - Paetel, S.
AU  - Heeg, T.
AU  - Pawlicki, A. A.
AU  - Kourkoutis, L. F.
AU  - Zheng, M.
AU  - Lee, M.
AU  - Mulcahy, B.
AU  - Zander, Willi
AU  - Zhu, Y.
AU  - Schubert, Jürgen
AU  - Eckstein, J. N.
AU  - Muller, D. A.
AU  - Hellberg, C. Stephen
AU  - Mannhart, J.
AU  - Schlom, D. G.
TI  - LaAlO3 stoichiometry is key to electron liquid formation at LaAlO3/SrTiO3 interfaces
JO  - Nature Communications
VL  - 4
SN  - 2041-1723
CY  - London
PB  - Nature Publishing Group
M1  - FZJ-2013-03754
SP  - 9
PY  - 2013
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000323753200012
C6  - pmid:23965846
DO  - DOI:10.1038/ncomms3351
UR  - https://juser.fz-juelich.de/record/137299
ER  -