Superconductivity in 1D Zigzag Nanowires*

We investigate the effects of the geometrical shapes of the 1D nanowires created at LaAlO₃/SrTiO₃ in order to study the origin of superconductivity of SrTiO₃, which has puzzled researchers for more than 50 years. It was recently suggested that electron pairing in SrTiO₃ may be related to ferroelastic domain walls [1]. By using conductive-AFM lithography [2] to create 1D superconducting nanowires at the LaAlO₃/SrTiO₃ interface, we can investigate the influence of nanowire shape, and in particular the effect of sharp turns in the nanowire, on superconducting behavior in the nanowires. We find a significant stabilization of the superconducting state in “zigzag” wires compared with straight control wires, both created at the same time and located only a few micrometers apart. We discuss possible origins for this behavior within the context of ferroelastic domain structure that surrounds the nanowires.

[1] Y.-Y. Pai, et al., Phys. Rev. Lett. 120, 147001 (2018).
[2] C. Cen, et al., Nature Materials 7, 298 (2008).