The oxide heterostructure LaAlO3/SrTiO3 supports a two-dimensional electron liquid with a variety of competing phases including magnetism, superconductivity and weak antilocalization due to Rashba spin-orbit coupling. Further confinement of this 2D e
lectron liquid to the quasi-one-dimensional regime can provide insight into the underlying physics of this system and reveal new behavior. Here we describe magnetotransport experiments on narrow LaAlO3/SrTiO3 structures created by a conductive atomic force microscope lithography technique. Four-terminal local transport measurements on ~10-nm-wide Hall bar structures yield longitudinal resistances that are comparable to the resistance quantum h/e2 and independent of the channel length. Large nonlocal resistances (as large as 10^4 ohms) are observed in some but not all structures with separations between current and voltage that are large compared to the 2D mean-free path. The nonlocal transport is strongly suppressed by the onset of superconductivity below ~200 mK. The origin of these anomalous transport signatures is not understood, but may arise from coherent transport defined by strong spin-orbit coupling and/or magnetic interactions.
We report superconductivity in quasi-1D nanostructures created at the LaAlO3/SrTiO3 interface. Nanostructures having line widths w~10 nm are formed from the parent two-dimensional electron liquid using conductive atomic force microscope lithography.
Nanowire cross-sections are small compared to the superconducting coherence length in LaAlO3/SrTiO3 (w<<xi~100 nm), placing them in the quasi-1D regime. Broad superconducting transitions with temperature and finite resistances in the superconducting state well below Tc~200 mK are observed. V-I curves show switching between the superconducting and normal states that are characteristic of superconducting nanowires. The four-terminal resistance in the superconducting state shows an unusual dependence on the current path, varying by as much as an order of magnitude.
