The LaAlO3/SrTiO3 system exhibits unusual magnetic and superconducting behavior arising from electron-electron interactions whose physical origin is not well understood. Quantum transport techniques, especially those involving mesoscopic geometries, can offer insight into these interactions. Here we report evidence for long-range electron-electron interactions in LaAlO3/SrTiO3 nanowires, measured through the phenomenon of frictional drag, in which current passing through one nanowire induces a voltage across a nearby electrically isolated nanowire. Frictional drag mediated by the Coulomb interaction is predicted to decay exponentially with interwire separation, but with the LaAlO3/SrTiO3 nanowire system it is found to be nearly independent of separation. Frictional drag experiments performed with three parallel wires demonstrates long-range frictional coupling even in the presence of an electrically grounded central wire. Collectively, these results provides evidence for a new long-range non-Coulombic electron-electron interaction unlike anything previously reported for semiconducting systems.
@article{arxiv.1707.01171,
title = {Long-range non-Coulombic electron-electron interactions between coupled LaAlO$_3$/SrTiO$_3$ nanowires},
author = {Yuhe Tang and Anthony Tylan-Tyler and Hyungwoo Lee and Michelle Tomczyk and Mengchen Huang and Chang-Beom Eom and Patrick Irvin and Jeremy Levy},
journal= {arXiv preprint arXiv:1707.01171},
year = {2019}
}