Engineering superconducting contacts transparent to a bipolar graphene

Fuente: arXiv
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Main Authors: Jang, Seong, Park, Geon-Hyoung, Park, Sein, Jeong, Hyeon-Woo, Watanabe, Kenji, Taniguchi, Takashi, Lee, Gil-Ho
Format: Preprint
Published: 2024
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_version_ 1866913737287401472
author Jang, Seong
Park, Geon-Hyoung
Park, Sein
Jeong, Hyeon-Woo
Watanabe, Kenji
Taniguchi, Takashi
Lee, Gil-Ho
author_facet Jang, Seong
Park, Geon-Hyoung
Park, Sein
Jeong, Hyeon-Woo
Watanabe, Kenji
Taniguchi, Takashi
Lee, Gil-Ho
contents Graphene's exceptional electronic mobility, gate-tunability, and contact transparency with superconducting materials make it ideal for exploring the superconducting proximity effect. However, the work function difference between graphene and superconductors causes unavoidable doping of graphene near contacts, forming a p-n junction in the hole-doped regime and reducing contact transparency. This challenges the device implementation that exploits graphene's bipolarity. To address this limitation, we developed a new fabrication scheme for two-dimensional superconducting contacts that allows independent control over charge concentration and polarity for both the graphene in contact with superconductors and the graphene channel. Contact transparency, conductance enhancement, and Josephson coupling were measured to confirm transparent contacts to both polarities of graphene. Moreover, we demonstrated the Andreev process in the quantum Hall edge state at a negative filling factor of ν = -2. This scheme will open avenues for realizing various theoretical propositions utilizing the bipolarity of graphene combined with superconductivity.
format Preprint
id arxiv_https___arxiv_org_abs_2411_17097
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Engineering superconducting contacts transparent to a bipolar graphene
Jang, Seong
Park, Geon-Hyoung
Park, Sein
Jeong, Hyeon-Woo
Watanabe, Kenji
Taniguchi, Takashi
Lee, Gil-Ho
Mesoscale and Nanoscale Physics
Superconductivity
Graphene's exceptional electronic mobility, gate-tunability, and contact transparency with superconducting materials make it ideal for exploring the superconducting proximity effect. However, the work function difference between graphene and superconductors causes unavoidable doping of graphene near contacts, forming a p-n junction in the hole-doped regime and reducing contact transparency. This challenges the device implementation that exploits graphene's bipolarity. To address this limitation, we developed a new fabrication scheme for two-dimensional superconducting contacts that allows independent control over charge concentration and polarity for both the graphene in contact with superconductors and the graphene channel. Contact transparency, conductance enhancement, and Josephson coupling were measured to confirm transparent contacts to both polarities of graphene. Moreover, we demonstrated the Andreev process in the quantum Hall edge state at a negative filling factor of ν = -2. This scheme will open avenues for realizing various theoretical propositions utilizing the bipolarity of graphene combined with superconductivity.
title Engineering superconducting contacts transparent to a bipolar graphene
topic Mesoscale and Nanoscale Physics
Superconductivity
url https://arxiv.org/abs/2411.17097