Quantized conductance through reconfigurable 1D channels

In recent years, a high mobility two-dimensional electron gas LaAlO$_3$/SrTiO$_3$ (LAO/STO) system has become a model system to investigate various exotic ground states of condensed matter physics. This system can co-host superconductivity, magnetism, and strong spin-orbit coupling at 2D interfaces which led to predictions of exotic phenomena such as unconventional superconductivity, helical/chiral modes, and Majorana phases in these interfaces. In order to explore these exotic phases high quality 1D devices are desirable. We demonstrate the realization of a gate tunable quantum point contact (QPC) structure embedded in a LAO/STO nanowire created using conductive AFM lithography. We observe integer quantized conductance in the units of $e^2/h$ at high magnetic fields ($B=9$ Tesla, $T=50$ mK),a signature of the existence of 1D quantum channels. Significantly, we observe quantized conduction for nanowires as long as 1 $\mu$m, implying that transport is ballistic along the magnetic-field induced chiral edge states in these devices.