Charge origin and localization at then-typeSrTiO3/LaAlO3interface

Abstract

We report a first-principles study of ͑LaAlO 3 ͒ m / ͑SrTiO 3 ͒ n heterostructures using density-functional theory at the LDA+ U level. Our results support the original explanation of Ohtomo and Hwang ͓Nature ͑London͒ 427, 423 ͑2004͔͒ that the charge at the n-type interface may be due to electrostatic doping. The internal electric field in the LaAlO 3 layer is calculated to be 0.24 V / Å. Though it is not sufficient to cause the dielectric breakdown in a wide band-gap La aluminate, it causes charge transfer into the adjacent narrower gap SrTiO 3 layer. The quasi-two-dimensional nature of the charge distribution is caused by a combination of the crystal-field effect, pseudo-Jahn-Teller distortion, and interface chemistry. Our theoretical estimate suggests that the interfacial carrier density of about 2 ϫ 10 13 cm −2 can be easily achieved.

Highly Spin-Polarized Conducting State at the Interface between Nonmagnetic Band Insulators:LaAlO3/FeS2(001)

“…2(a) [36].) This behavior is consistent with the charge transfer mechanism known for the well-studied LaAlO 3 =SrTiO 3 system [9,37,38]. The charge transfer amounts to $0:16 electrons/interface Fe.…”

Creation of a two-dimensional electron gas at an oxide interface on silicon

“…The discovery of a 2DEG (ref. 3) at the heterointerface between band insulators LaAlO 3 (LAO) and SrTiO 3 (STO) has launched many experimental [2][3][4][5][6][7][8][9][10][11][12]16 and theoretical 13,17,18 investigations of the fundamental origins and properties of this novel electronic state. Thiel et al 7 reported non-volatile electrical control of a metal-insulator quantum phase transition in LAO/STO heterointerface at room temperature.…”

“…H eterointerfaces between different oxide layers can display remarkable electrical properties 1 that differ from either constituent, such as a two-dimensional electron gas (2DEG, refs [2][3][4][5][6][7][8][9][10][11][12][13][14] and interfacial superconductivity 15 . The discovery of a 2DEG (ref.…”

Large phonon-drag enhancement induced by narrow quantum confinement at theLaAlO3/SrTiO3interface

“…Exploiting the flexibility of band modeling, we thus treat them as variable parameters to explore the phonondrag behavior in a range of different conditions. For what concern the 2DES thickness, ab-initio results 33,[63][64][65][66][67][68][69][70][71][72] show that for the charge density of interest (∼2-4×10 13 cm −2 ) the gas is entirely included in a few (∼2,3) d xy states confined in the TiO 2 layers closest to the interface, while only above ∼ 6×10 13 cm −2 the more extended d xz , d yz states sets in. However, in order to evaluate the scaling with respect to the 2D confinement, it is convenient to replace the actual squared wavefunctions with Gaussian envelope functions of variable thickness t (see Appendix-I for details).…”