@article{6dfa61d3d8274edeabe432fd2276e17e,
title = "LaAlO 3 stoichiometry is key to electron liquid formation at LaAlO 3/SrTiO 3 interfaces",
abstract = "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 (SrTiO 3) 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/SrTiO 3 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.",
author = "Warusawithana, {M. P.} and C. Richter and Mundy, {J. A.} and P. Roy and J. Ludwig and S. Paetel and T. Heeg and Pawlicki, {A. A.} and Kourkoutis, {L. F.} and M. Zheng and M. Lee and B. Mulcahy and W. Zander and Y. Zhu and J. Schubert and Eckstein, {J. N.} and Muller, {D. A.} and Hellberg, {C. Stephen} and J. Mannhart and Schlom, {D. G.}",
note = "Funding Information: We acknowledge discussions and interactions with Scott Chambers, Noam Bernstein, J. Grazul, J. Aarts, J. Brooks and E. J. Kirkland. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1157490, the State of Florida, and the US Department of Energy (M.P.W., P.R., J.L., A.A.P., M.L.). In addition, the financial support of the Deutsche Forschungsgemeinschaft (TRR 80) (C.R., S.P., J.M.), European Community (OxIDes) (C.R., S.P., J.M.), the National Science Foundation through the MRSEC programme (DMR-1120296) (T.H., L.F.K.), Office of Naval Research through the Naval Research Laboratory{\textquoteright}s Basic Research Program (C.S.H.), NSF graduate fellowship DGE-0707428 (J.A.M.), the D.O.D. through an NDSEG fellowship (J.A.M.) and Army Research Office ARO #W911NF0910415 (Y.Z., D.A.M., D.G.S.) is gratefully acknowledged. Computations were performed at the ERDC DoD Major Shared Resource Center.",
year = "2013",
doi = "10.1038/ncomms3351",
language = "English (US)",
volume = "4",
journal = "Nature communications",
issn = "2041-1723",
publisher = "Nature Research",
}