Strong Aharonov-Bohm quantum interference in simply connected LaAlO3/ SrTiO3 structures

We report Aharonov-Bohm (AB) type quantum interference in simply connected devices created at the LaAlO3/SrTiO3 interface using conductive atomic force microscope (c-AFM) lithography. The oscillations are multiperiodic functions of magnetic field strength, and they exhibit a substantial magnetic hysteresis with frequencies that depend on the magnetic sweep direction. The oscillation amplitude for the lowest two frequencies approaches e2/h, consistent with the theoretical maximum for the AB effect, and harmonics up to third order are observable. Broadband quasiperiodic behavior is reported in a fraction of simply connected electron waveguide devices that exhibit magnetic asymmetries. Curiously, nanoscale ring devices that are multiply connected lack signatures of AB quantum interference. The interference phenomena are associated with an inhomogeneous magnetic landscape within the LaAlO3/SrTiO3 nanostructures.