TY - JOUR
T1 - LaAlO 3 stoichiometry is key to electron liquid formation at LaAlO 3/SrTiO 3 interfaces
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, W.
AU - Zhu, Ye
AU - Schubert, J.
AU - Eckstein, J. N.
AU - Muller, D. A.
AU - Hellberg, C. Stephen
AU - Mannhart, J.
AU - Schlom, D. G.
PY - 2013/9/3
Y1 - 2013/9/3
N2 - 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 LaAlO3has been assumed perfect. Here we demonstrate, through experiments and first-principle calculations, that the cation stoichiometry of the nominal LaAlO3layer is key to 2-DEL formation: only Al-rich LaAlO3results in a 2-DEL. Although extrinsic defects, including oxygen deficiency, are known to render LaAlO3/SrTiO3samples 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.
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 LaAlO3has been assumed perfect. Here we demonstrate, through experiments and first-principle calculations, that the cation stoichiometry of the nominal LaAlO3layer is key to 2-DEL formation: only Al-rich LaAlO3results in a 2-DEL. Although extrinsic defects, including oxygen deficiency, are known to render LaAlO3/SrTiO3samples 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.
UR - https://www.scopus.com/pages/publications/84883157981
U2 - 10.1038/ncomms3351
DO - 10.1038/ncomms3351
M3 - Journal article
SN - 2041-1723
VL - 4
JO - Nature Communications
JF - Nature Communications
M1 - 2351
ER -