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Main Authors: Park, Geon-Hyoung, Lee, Wonjun, Park, Sein, Watanabe, Kenji, Taniguchi, Takashi, Cho, Gil Young, Lee, Gil-Ho
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2312.02640
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author Park, Geon-Hyoung
Lee, Wonjun
Park, Sein
Watanabe, Kenji
Taniguchi, Takashi
Cho, Gil Young
Lee, Gil-Ho
author_facet Park, Geon-Hyoung
Lee, Wonjun
Park, Sein
Watanabe, Kenji
Taniguchi, Takashi
Cho, Gil Young
Lee, Gil-Ho
contents We demonstrate that the mode number of Andreev bound states in bilayer graphene Josephson junctions can be modulated by in situ control of the superconducting coherence length. By exploiting the quadratic band dispersion of bilayer graphene, we control the Fermi velocity and thus the coherence length by the application of the electrostatic gating. Tunneling spectroscopy of Andreev bound states reveals a crossover from short to long Josephson junction regimes as the gate voltage is approached near the charge neutral point of bilayer graphene. Furthermore, quantitative analysis of Andreev spectrums for different mode numbers allows us to quantitatively estimate the phase-dependent Josephson current. Our work paves a new way to study multi-mode Andreev levels and to engineer Fermi velocity with bilayer graphene.
format Preprint
id arxiv_https___arxiv_org_abs_2312_02640
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Controllable Andreev Bound States in Bilayer Graphene Josephson Junction from Short to Long Junction Limits
Park, Geon-Hyoung
Lee, Wonjun
Park, Sein
Watanabe, Kenji
Taniguchi, Takashi
Cho, Gil Young
Lee, Gil-Ho
Mesoscale and Nanoscale Physics
We demonstrate that the mode number of Andreev bound states in bilayer graphene Josephson junctions can be modulated by in situ control of the superconducting coherence length. By exploiting the quadratic band dispersion of bilayer graphene, we control the Fermi velocity and thus the coherence length by the application of the electrostatic gating. Tunneling spectroscopy of Andreev bound states reveals a crossover from short to long Josephson junction regimes as the gate voltage is approached near the charge neutral point of bilayer graphene. Furthermore, quantitative analysis of Andreev spectrums for different mode numbers allows us to quantitatively estimate the phase-dependent Josephson current. Our work paves a new way to study multi-mode Andreev levels and to engineer Fermi velocity with bilayer graphene.
title Controllable Andreev Bound States in Bilayer Graphene Josephson Junction from Short to Long Junction Limits
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2312.02640