The spin-orbit interaction couples the electrons' motion to their spin. Accordingly, passing a current in a material with strong spin-orbit coupling generates a transverse spin current (spin Hall effect, SHE) and vice-versa (inverse spin Hall effect, ISHE) 1-3 . The emergence of SHE and ISHE as charge-to-spin interconversion mechanisms offers a variety of novel spintronics functionalities 4,5 and devices, some of which do not require any ferromagnetic material 6 . However, the interconversion efficiency of SHE and ISHE (spin Hall angle) is a bulk property that rarely exceeds ten percent, and does not take advantage of interfacial and low-dimensional effects otherwise ubiquitous in spintronics hetero-and mesostructures. Here, we make use of an interface-driven spin-orbit coupling mechanism  the Rashba effect 7  in the oxide two-dimensional electron system (2DES) LaAlO3/SrTiO3 to achieve spin-to-charge conversion with unprecedented efficiency. Through spin-pumping, we inject a spin current from a NiFe film into the oxide 2DES and detect the resulting charge current, which can be strongly modulated by a gate voltage. We discuss the amplitude of the effect and its gate dependence on the basis of the electronic structure of the 2DES. Perovskite oxide materials possess a broad range of functionalities, some of which can be very appealing for spintronics. This includes half-metallicity in mixed-valence manganites  that can be used to produce giant tunnel magnetoresistance 8  or multiferroicity  through which magnetization direction can be electrically controlled at low power 9 . The recent years have seen the emergence of novel spintronics effects based on the generation and control of pure spin currents through spin-orbit effects in semiconducting and metallic systems 1-3 . However, despite a renewal of interest for 4d and 5d transition metal perovksites 10 , spin-orbit effects remained largely unexplored in oxide spintronics.An emerging direction in oxide research aims at discovering novel electronic phases at interfaces between two oxide materials 11 . A well-known example is the LaAlO3/SrTiO3 system: while both LaAlO3 (LAO) and SrTiO3 (STO) are wide bandgap semiconductors, a high-mobility two-dimensional electron system (2DES) forms at their interface 12 if the LAO thickness is at least 4 unit-cells (uc). Interestingly, LAO/STO possesses several remarkable extra functionalities including a gate-tuneable Rashba effect 13,14 , which makes it particularly appealing for spintronics.The Rashba effect is a manifestation of the spin-orbit interaction (SOI) in solids, where spin degeneracy associated with the spatial inversion symmetry is lifted due to a symmetry-breaking electric field normal to an heterointerface 15 . In a Rashba 2DES, the flow of a charge current results in the creation of a nonzero spin accumulation 16,17 coming from uncompensated spin-textured Fermi surfaces. Recently, the converse effect so-called inverse Edelstein effect (IEE)  that is a spin-to-charge conversion through SOI  was discovered a...

In LaTiO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures, the bending of the SrTiO3 conduction band at the interface forms a quantum well that contains a superconducting two-dimensional electron gas (2-DEG). Its carrier density and electronic properties, such as superconductivity and Rashba spin-orbit coupling can be controlled by electrostatic gating. In this article we show that the Fermi energy lies intrinsically near the top of the quantum well. Beyond a filling threshold, electrons added by electrostatic gating escape from the well, hence limiting the possibility to reach a highly-doped regime. This leads to an irreversible doping regime where all the electronic properties of the 2-DEG, such as its resistivity and its superconducting transition temperature, saturate. The escape mechanism can be described by the simple analytical model we propose.

The recent development in the fabrication of artificial oxide heterostructures opens new avenues in the field of quantum materials by enabling the manipulation of the charge, spin and orbital degrees of freedom. In this context, the discovery of two-dimensional electron gases (2-DEGs) at LaAlO3/SrTiO3 interfaces, which exhibit both superconductivity and strong Rashba spin-orbit coupling (SOC), represents a major breakthrough. Here, we report on the realisation of a field-effect LaAlO3/SrTiO3 device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage. We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition. Magneto-transport measurements show that the Rashba coupling constant increases linearly with the interfacial electric field. Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates.