Spontaneous 2-Dimensional Carrier Confinement at the n-Type SrTiO3/LaAlO3 Interface

被引:180
作者
Delugas, Pietro [1 ]
Filippetti, Alessio [1 ]
Fiorentini, Vincenzo [1 ]
Bilc, Daniel I. [2 ]
Fontaine, Denis [2 ]
Ghosez, Philippe [2 ]
机构
[1] Univ Cagliari, Dipartimento Fis, CNR IOM UOS Cagliari, I-09042 Monserrato, CA, Italy
[2] Univ Liege, B-4000 Sart Tilman Par Liege, Belgium
关键词
OXIDE HETEROSTRUCTURES;
D O I
10.1103/PhysRevLett.106.166807
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
We describe the intrinsic mechanism of 2-dimensional electron confinement at the n-type SrTiO3/LaAlO3 interface as a function of the sheet carrier density n(s) via advanced first-principles calculations. Electrons localize spontaneously in Ti 3d(xy) levels within a thin (less than or similar to 2 nm) interface-adjacent SrTiO3 region for n(s) lower than a threshold value n(c) similar to 10(14) cm(-2). For n(s) > n(c) a portion of charge flows into Ti 3d(xz)-d(yz) levels extending farther from the interface. This intrinsic confinement can be attributed to the interface-induced symmetry breaking and localized nature of Ti 3d t(2g) states. The sheet carrier density directly controls the binding energy and the spatial extension of the conductive region. A direct, quantitative relation of these quantities with n(s) is provided.
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页数:4
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