Transport properties of the complex oxide LaAlO3/SrTiO3 interface are investigated under high magnetic field (55T). By rotating the sample with respect to the magnetic field, the two-dimensional nature of charge transport is clearly established. Small oscillations of the magnetoresistance with altered periodicity are observed when plotted versus inverse magnetic field. We attribute this effect to Rashba spin-orbit coupling which remains consistent with large negative magnetoresistance when the field is parallel to the sample plane. A large inconsistency between the carrier density extracted from Shubnikov-de Haas analysis and from the Hall effect is explained by the contribution to transport of at least two bands with different mobility.Oxide interfaces constitute a rapidly developing field of research, with potential applications in electronics [1, 2] or solar energy harvesting [3]. There is currently a focus on the band-insulators LaAlO 3 (LAO) and SrTiO 3 (STO), which host a conducting two-dimensional electron gas (2DEG) at their interface [4]. It is mainly believed to originate from the polar catastrophe [5], which results in a charge transfer between the polar oxide [100] LAO and the nonpolar oxide [100] STO. This charge transfer prevents a divergence of the electrostatic potential associated with the intra-layer built-in electric field. Charge accumulation is therefore predicted at the interface with intriguing consequences such as magnetism [6] and superconductivity [7]. In LAO/STO heterostructures, symmetry-lowering at the interface raises the Ti t 2g band degeneracy so that the d xy orbital is lower in energy than the d xz and d yz orbitals. Depending on the total two-dimensional carrier density, the band occupation and the spatial distribution of the carriers [8] [12,14,15], opening new perspectives for the investigation of the charge carriers' properties in relation to their band-structure. However, quantum transport studies remain scarce in the literature and the large variability in the results (originating from the large range of samples studied) does not yet offer a clear picture of electron transport in LAO/STO. In this context, we make use of very large magnetic field (55 T) to extend the range of magnetoresistance measurements and enhance the visibility of SdH oscillations. We interpret our experimental data by the presence of low and high mobility electrons both contributing to transport, and confirm the role of Rashba spin-orbit coupling.Two samples named S 1 and S 2 were obtained by depositing 10 unit cells of LAO on TiO 2 -terminated (100)-oriented STO substrates using pulsed laser deposition (PLD) [16]. Since both samples displayed similar results, we shall mainly discuss sample S 1 and make reference to sample S 2 only when relevant (full data for sample S 2 are available in the Supplemental Information). The LAO was grown at T=740 o C in oxygen partial pressure of P O2 = 2 × 10 −3 Torr. During the deposition, in-situ reflection high energy electron diffraction (RHEED) was used to preci...
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