The superconducting transport properties of the conducting ${\text{LaAlO}}_3/{\text{SrTiO}}_3$ interface have been investigated in perpendicular and parallel magnetic fields. A large anisotropy in the transport properties is measured and the two-dimensional nature of the superconducting gas is confirmed. Analyses of the resistance versus temperature and magnetic field, as well as of the correlation length as a function of the magnetic field close to the superconducting critical temperature (about 200 mK), yield an estimate of $\sim 10\text{nm}$ for the superconducting layer thickness.

In this review, we focus on the celebrated interface between two band insulators, LaAlO₃ and SrTiO₃, that was found to be conducting, superconducting, and to display a strong spin-orbit coupling. We discuss the formation of the 2-dimensional electron liquid at this interface, the particular electronic structure linked to the carrier confinement, the transport properties, and the signatures of magnetism. We then highlight distinctive characteristics of the superconducting regime, such as the electric field effect control of the carrier density, the unique tunability observed in this system, and the role of the electronic subband structure. Finally we compare the behavior of T_c versus 2D doping with the dome-like behavior of the 3D bulk superconductivity observed in doped SrTiO₃. This comparison reveals surprising differences when the T_c behavior is analyzed in terms of the 3D carrier density for the interface and the bulk.

Understanding the nature of charge carriers at the LaAlO₃/SrTiO₃ interface is one of the major open issues in the full comprehension of the charge confinement phenomenon in oxide heterostructures. Here, we investigate thermopower to study the electronic structure in LaAlO₃/SrTiO₃ at low temperature as a function of gate field. In particular, under large negative gate voltage, corresponding to the strongly depleted charge density regime, thermopower displays high negative values of the order of 10⁴–10⁵μVK⁻¹, oscillating at regular intervals as a function of the gate voltage. The huge thermopower magnitude can be attributed to the phonon-drag contribution, while the oscillations map the progressive depletion and the Fermi level descent across a dense array of localized states lying at the bottom of the Ti 3d conduction band. This study provides direct evidence of a localized Anderson tail in the two-dimensional electron liquid at the LaAlO₃/SrTiO₃ interface.