Shubnikov-de Haas oscillations in SrTiO3\LaAlO3 interface

Quantum magnetic oscillations in SrTiO3/\LaAlO3 interface are observed. The evolution of their frequency and amplitude at various gate voltages and temperatures is studied. The data are consistent with the Shubnikov de-Haas theory. The Hall resistivity rho exhibits nonlinearity at low magnetic field. It is fitted assuming multiple carrier contributions. The comparison between the mobile carrier density inferred from the Hall data and the oscillation frequency suggests multiple valley and spin degeneracy. The small amplitude of the oscillations is discussed in the framework of the multiple band scenario

Tuning spin-orbit coupling and superconductivity at the SrTiO3/LaAlO3 interface: a magneto-transport study

The superconducting transition temperature, Tc, of the SrTiO3/LaAlO3 interface was varied by the electric field effect. The anisotropy of the upper critical field and the normal state magneto-transport were studied as a function of gate voltage. The spin-orbit coupling energy is extracted. This tunable energy scale is used to explain the strong gate dependence of the mobility and of the anomalous Hall signal observed. The spin-orbit coupling energy follows Tc for the electric field range under study

Phase coherent transport in SrTiO3/LaAlO3 interfaces

The two dimensional electron gas formed between the two band insulators SrTiO3 and LaAlO3 exhibits a variety of interesting physical properties which make it an appealing material for use in future spintronics and/or quantum computing devices. For this kind of applications electrons have to retain their phase memory for sufficiently long times or length. Using a mesoscopic size device we were able to extract the phase coherence length, and its temperature variation. We find the dephasing rate to have a power law dependence on temperature. The power depends on the temperature range studied and sheet resistance as expected from dephasing due to strong electron-electron interactions.Comment: Submitted to Phys. Rev

Luttinger liquid behavior in weakly disordered quantum wires

We have measured the temperature dependence of the conductance in long V-groove quantum wires (QWRs) fabricated in GaAs/AlGaAs heterostructures. Our data is consistent with recent theories developed within the framework of the Luttinger liquid model, in the limit of weakly disordered wires. We show that for the relatively small amount of disorder in our QWRs, the value of the interaction parameter g is g=0.66, which is the expected value for GaAs. However, samples with a higher level of disorder show conductance with stronger temperature dependence, which does not allow their treatment in the framework of perturbation theory. Trying to fit such data with perturbation-theory models leads inevitably to wrong (lower) values of g.Comment: 4 pages, 4 figure