The superconducting transition temperature T{c} of the SrTiO{3}/LaAlO{3} interface was varied by the electric field effect. The anisotropy of the upper critical field and the normal-state magnetotransport were studied as a function of gate voltage. The spin-orbit coupling energy epsilon{SO} is extracted. This tunable energy scale is used to explain the strong gate dependence of the mobility and of the anomalous Hall signal observed. Epsilon{SO} follows T{c} for the electric field range under study.

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 ρxy exhibits nonlinearity at low magnetic field. ρxy 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. PACS numbers: 75.70.Cn, The two dimensional electron gas (2DEG) formed at the interface between two insulating perovskites is a subject of intense scientific interest.[1] The most widely studied interface has been the one created between SrTiO 3 and LaAlO 3 .[2] At low temperatures this 2DEG has a superconducting ground state, whose critical temperature can be modified by an electric field effect.[3]The nature of the charge carriers and their origin are still a matter of debate. [4][5][6][7][8][9][10][11] The thickness of the conducting layer has been estimated to be of a few nanometers by both transport measurements [12][13] and by using a conducting atomic force microscope (AFM). [14] From the AFM data analysis Copie et al. conclude that two types of charge carriers screen the local electric fields. The magnetoresistance is strongly anisotropic [12] and effected by a gate dependent spin-orbit interaction. [15,16] The ρ xy is non linear in magnetic field, [15,17] and therefore it does not relate in a simple way to the number of charge carriers. The effective mass has been estimated using elipsometry[18] to be 2.2 m e with m e the electron mass. The number of charge carriers, their effective mass and the effect of gate voltage on their mobility are a subject of vigorous research.Quantum oscillations in magnetic fields have been extensively used to study the electronic properties of metals semiconductors and correlated systems. In the standard theory of Shubnikov-de Haas (SdH) the amplitude of the oscillating part of the resistance is [19]Where R c is the non-oscillating part of the resistance. The oscillation amplitude decays with temperature as given bywith m * the quasiparticle effective mass. The Dingle factor iswith ω c = eB m * and τ D the Dingle scattering time, which is related to the Dingle temperature by k B T D = /2πτ D . This factor determines the decay of the amplitude of the oscillations as the field decreases. Increasing the magnetic field, lowering the temperatures and decreasing the scattering rate should all lead to increasing oscillations amplitude.In this letter we report longitudinal and Hall resistance measurements at low temperatures and intense magnetic fields of up to 31.5 T. The high magnetic field enables us to detect quantum oscillations in the longitudinal resistivity, as well as nonlinearities in the Hall resistance. The data are consistent with the SdH theory, enabling us to extract ...

We measured the long term spontaneous electrical activity of neuronal networks with different sizes, grown on lithographically prepared substrates and recorded with multi-electrode-array technology. The time sequences of synchronized bursting events were used to characterize network dynamics. All networks exhibit scale-invariant Lévy distributions and long-range correlations. These observations suggest that different-size networks self-organize to adjust their activities over many time scales. As predictions of current models differ from our observations, this calls for revised models.

We report on experimental studies of superconductor-ferromagnet layered structures. Strong oscillations of the critical supercurrent were observed with the thickness variation of the ferromagnet. Using known microscopic parameters of Ni, we found reasonable agreement between the period of oscillations and the decay of the measured critical current, and theoretical calculations.

The search for broken time reversal symmetry (TRSB) in unconventional superconductors intensified in the past year as more systems have been predicted to possess such a state. Following our pioneering study of TRSB states in Sr2RuO4 using magneto-optic probes, we embarked on a systematic study of several other of these candidate systems. The primary instrument for our studies is the Sagnac magneto-optic interferometer, which we recently developed. This instrument can measure magneto-optic Faraday or Kerr effects with an unprecedented sensitivity of 10 nanoradians at temperatures as low as 100 mK. In this paper we review our recent studies of TRSB in several systems, emphasizing the study of the pseudogap state of high temperature superconductors and the inverse proximity effect in superconductor/ferromagnet proximity structures.