Quantized critical supercurrent in SrTiO$_3$-based quantum point contacts

TL;DR

This paper demonstrates quantized critical supercurrents in SrTiO$_3$-based quantum point contacts, showcasing the material's potential for mesoscopic superconducting devices and topological superconductivity engineering.

Contribution

It introduces nanoscale weak links in SrTiO$_3$ with electrostatically tunable supercurrents, advancing the use of SrTiO$_3$ as a platform for superconducting quantum devices.

Findings

Superconducting quantum point contacts exhibit quantized critical supercurrents.

Electrostatic gating controls supercurrent in SrTiO$_3$ devices.

Milestone for topological superconductivity research in SrTiO$_3$.

Abstract

Superconductivity in SrTiO$_3$ occurs at remarkably low carrier densities and therefore, unlike conventional superconductors, can be controlled by electrostatic gates. Here we demonstrate nanoscale weak links connecting superconducting leads, all within a single material, SrTiO$_3$. Ionic liquid gating accumulates carriers in the leads, and local electrostatic gates are tuned to open the weak link. These devices behave as superconducting quantum point contacts with a quantized critical supercurrent. This is a milestone towards establishing SrTiO$_3$ as a single-material platform for mesoscopic superconducting transport experiments, that also intrinsically contains the necessary ingredients to engineer topological superconductivity