Scanning Gate Microscopy Modulation of Supercurrent in Graphene Josephson Junctions
arXiv:2607.26689
The paper uses scanning gate microscopy to locally modulate and map the supercurrent in hBN‑encapsulated graphene Josephson junctions with niobium contacts, analyzing how tip voltage and distance affect the critical current and confirming the observations with simulations.
Abstract
Graphene Josephson junctions represent an excellent platform for quantum technologies, thanks to the combination of high carrier mobility, ballistic transport, and large gate-tunable critical currents, preserved even under quantizing magnetic fields. Investigating the spatial distribution of supercurrent flow could be crucial for elucidating transport mechanisms and advancing the engineering of these devices. In this work, we employ a Scanning Gate Microscope to investigate supercurrent transport in hBN-encapsulated graphene Josephson junctions contacted by Niobium leads. We study the supercurrent modulation as a function of the applied tip voltage bias and tip-to-sample distance, and provide a complete characterization of the tip-induced modulation. Our experimental results are quantitatively consistent with numerical simulations and pave the way towards local mapping and manipulation of gate-tunable superconducting phenomena with unprecedented spatial resolution.
25 pages, 9 figures