Nonlocal current-voltage characteristics of gated superconducting sketched oxide nanostructures

¹ University of Pittsburgh - Pittsburgh, PA 15260, USA
² University of Wisconsin-Madison - Madison, WI 53706, USA

^(b) jlevy@pitt.edu

Received: 28 August 2013
Accepted: 30 August 2013

Abstract

Effects from nonequilibrium superconductivity play a major role in the physics of superconducting nanoelectronics. Notably, charge imbalance arising from the point at which the superconducting device contacts normal-metal leads is prevalent, particularly in reduced dimensions. We investigate nonlocal transport signatures in quasi-1D nanostructures formed at the LaAlO₃/SrTiO₃ interface. The nonlocal resistances correlate with the bias, magnetic field, and back gate dependence of the superconducting state. We attribute these signatures to charge imbalance or spin-dependent excitations. Understanding and control over these effects are important for further development of superconducting nanoelectronics in this material system, including the ability to probe the interaction of superconductivity and other rich physics in LaAlO₃/SrTiO₃ on the nanoscale.