Nanostructures*

We investigate the effects of uniaxial strain on superconductivity in nanowires created at the LaAlO₃/SrTiO₃ interface using conductive atomic force microscope (c-AFM) lithography ^[1]. C-AFM-written areas are associated with Z-oriented ferroelastic domains, surrounded by in-plane insulating regions ^[2]. Application of external uniaxial stress is expected to displace the ferroelastic domain boundaries, either inward or outward, depending on the sign. Our initial experiments indicate that tensile and compressive strains profoundly affect the superconducting state at milli-Kelvin temperatures. Uniaxial stretching of the nanowire in the parallel direction is found to completely suppress the superconducting state, while reversal of the applied strain restores superconductivity. We discuss implications for understanding possible role of ferroelastic domain walls in electron-pairing mechanisms.

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