Single-Mode Superconductivity in LaAlO 3 /SrTiO 3 Nanostructures

The properties of superconductors at the extreme limits of dimensionality are of fundamental interest. The interface of LaAlO 3 and SrTiO 3 hosts a quasi-two-dimensional superconductor below T c ≈200 mK. Here we report superconductivity in nanowire-shaped structures created at the LaAlO 3 /SrTiO 3 interface using conductive atomic force microscope lithography. Nanowire cross-sections are small compared to the superconducting coherence length in LaAlO 3 /SrTiO 3 ( w ξ SC ∼100 nm), placing them in the quasi-1D regime. The ability to “write” fully superconducting nanostructures on an insulating LaAlO 3 /SrTiO 3 “canvas” opens possibilities for the development of new families of superconducting nanoelectronics. Four-terminal transport measurements suggest that in some devices both the normal and superconducting states are confined to a single quantum channel.