Evidence of Josephson junction behavior in top-gated LaAlO$_3$-SrTiO$_3$

TL;DR

This paper reports the creation of tunable Josephson junctions at the LaAlO3-SrTiO3 interface using combined top-gate and back-gate techniques, revealing their behavior as short, overdamped weak links and aiding superconductivity studies.

Contribution

It introduces a novel top-gate tuning method for Josephson junctions in LaAlO3-SrTiO3, enabling finer control over their properties compared to traditional back-gating.

Findings

Junctions behave as short, overdamped weak links

Critical currents vary with temperature

Top-gate control enhances spatial precision

Abstract

We demonstrate top-gate tunable Josephson junction like behavior in the two dimensional electron gas at the LaAlO$_3$-SrTiO$_3$ interface. A combination of global back-gating and local top-gating is used to define the junctions, providing an efficient way for much finer spatial control over the properties of the interface, as compared to back-gating alone. The variation of critical currents and zero bias resistances with temperature shows that the junctions behave like short, overdamped weak links. This technique could be an important tool to illuminate the nature of superconductivity in the LaAlO$_3$-SrTiO$_3$ interface system.