Vertical Nb Josephson junctions fabricated by direct metal deposition on both surfaces of freestanding graphene layers

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Kim, Yoonkang, Kim, Seongbeom, Kim, Jeonglyul, Jung, Kikyung, An, Sejin, Lee, Jieun, Yoo, Hyobin, Park, Joon Young, Yi, Gyu-Chul
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914306772172800
author Kim, Yoonkang
Kim, Seongbeom
Kim, Jeonglyul
Jung, Kikyung
An, Sejin
Lee, Jieun
Yoo, Hyobin
Park, Joon Young
Yi, Gyu-Chul
author_facet Kim, Yoonkang
Kim, Seongbeom
Kim, Jeonglyul
Jung, Kikyung
An, Sejin
Lee, Jieun
Yoo, Hyobin
Park, Joon Young
Yi, Gyu-Chul
contents Vertical integration of superconducting electronics requires fabrication strategies that preserve pristine interfaces while accommodating oxidation-sensitive elemental superconductors. However, existing van der Waals-based vertical Josephson junctions largely rely on transfer-based assembly schemes that are incompatible with elemental materials such as niobium (Nb). Here, we introduce a freestanding van der Waals membrane architecture that enables deposition-based fabrication of vertical Josephson junctions through double-sided processing of a single suspended two-dimensional layer. Using multilayer graphene suspended across lithographically defined through-holes in a SiNx membrane, we realize vertical Nb/multilayer graphene/Nb Josephson junctions without ambient exposure of buried interfaces. The resulting devices exhibit clear Josephson coupling, including reproducible supercurrents and a temperature dependence of the critical current consistent with short-junction behaviour. Well-defined magnetic interference patterns governed by the membrane-defined aperture geometry, together with sub-gap features that track a Bardeen-Cooper-Schrieffer (BCS)-like superconducting gap, further confirm the junction quality. This platform establishes a scalable route to vertical superconducting devices based on oxidation-sensitive elemental superconductors and van der Waals materials.
format Preprint
id arxiv_https___arxiv_org_abs_2602_05170
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Vertical Nb Josephson junctions fabricated by direct metal deposition on both surfaces of freestanding graphene layers
Kim, Yoonkang
Kim, Seongbeom
Kim, Jeonglyul
Jung, Kikyung
An, Sejin
Lee, Jieun
Yoo, Hyobin
Park, Joon Young
Yi, Gyu-Chul
Superconductivity
Mesoscale and Nanoscale Physics
Materials Science
Vertical integration of superconducting electronics requires fabrication strategies that preserve pristine interfaces while accommodating oxidation-sensitive elemental superconductors. However, existing van der Waals-based vertical Josephson junctions largely rely on transfer-based assembly schemes that are incompatible with elemental materials such as niobium (Nb). Here, we introduce a freestanding van der Waals membrane architecture that enables deposition-based fabrication of vertical Josephson junctions through double-sided processing of a single suspended two-dimensional layer. Using multilayer graphene suspended across lithographically defined through-holes in a SiNx membrane, we realize vertical Nb/multilayer graphene/Nb Josephson junctions without ambient exposure of buried interfaces. The resulting devices exhibit clear Josephson coupling, including reproducible supercurrents and a temperature dependence of the critical current consistent with short-junction behaviour. Well-defined magnetic interference patterns governed by the membrane-defined aperture geometry, together with sub-gap features that track a Bardeen-Cooper-Schrieffer (BCS)-like superconducting gap, further confirm the junction quality. This platform establishes a scalable route to vertical superconducting devices based on oxidation-sensitive elemental superconductors and van der Waals materials.
title Vertical Nb Josephson junctions fabricated by direct metal deposition on both surfaces of freestanding graphene layers
topic Superconductivity
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2602.05170