interface via uniaxial strain*

Oxide interfaces offer new ways to probe superconductivity in reduced spatial dimensions.  Using conductive atomic force microscope (c-AFM) lithography [1], conductive nanostructures can be reversibly created at the LaAlO₃/SrTiO₃ interface, showing superconductivity at sub-Kelvin temperatures.  Here we focus on the effects of uniaxial stress on the transport of superconducting quantum wires formed at the LaAlO₃/SrTiO₃ interface.  We find that superconductivity is strongly affected by uniaxial strain applied parallel to the nanowire direction and in the transverse directions.  Under certain conditions, we find that minute changes in uniaxial strain can abruptly and reversibly switch LaAlO₃/SrTiO₃ nanowires from a superconducting state to a normal state.  We will discuss the implications of these results on possible electron-pairing mechanisms.

[1] C. Cen, et al., Nature Materials 7, 298 (2008).