Magnetic field tuned superconductor-to-insulator transition at the LaAlO₃/ SrTiO₃interface

We present a study of the magnetic field tuned superconductor-to-insulator transition (SIT) in the electron gas that forms at the LaAlO₃/SrTiO₃interface. We find that the magnetic field induces a transition into a weakly insulating state, as is observed for the electrostatically tuned SIT at this interface. Finite size scaling of the magnetoresistance yields the critical exponent product zν≃7/3, indicating that the transition is governed by quantum percolation effects. While such critical exponents have been reported previously for high resistance films, they have not been reported for a low resistance system like ours, with a maximum sheet resistance of ≈1.5 kΩ, much less than the quantum of resistance RQ≡h/4e2=6.45 kΩ.