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Research output: Contribution to Journal/Magazine › Letter › peer-review
Quantum oscillations of the critical current and high-field superconducting proximity in ballistic graphene. / Ben Shalom, M.; Zhu, M. J.; Fal'ko, V. I. et al.
In: Nature Physics, Vol. 12, No. 4, 04.2016, p. 318-322.Research output: Contribution to Journal/Magazine › Letter › peer-review
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TY - JOUR
T1 - Quantum oscillations of the critical current and high-field superconducting proximity in ballistic graphene
AU - Ben Shalom, M.
AU - Zhu, M. J.
AU - Fal'ko, V. I.
AU - Mishchenko, A.
AU - Kretinin, A. V.
AU - Novoselov, K. S.
AU - Woods, C. R.
AU - Watanabe, K.
AU - Taniguchi, T.
AU - Geim, A. K.
AU - Prance, Jonathan Robert
PY - 2016/4
Y1 - 2016/4
N2 - Graphene-based Josephson junctions provide a novel platform for studying the proximity effect due to graphene’s unique electronic spectrum and the possibility to tune junction properties by gate voltage. Here we describe graphene junctions with a mean free path of several micrometres, low contact resistance and large supercurrents. Such devices exhibit pronounced Fabry–Pérot oscillations not only in the normal-state resistance but also in the critical current. The proximity effect is mostly suppressed in magnetic fields below 10 mT, showing the conventional Fraunhofer pattern. Unexpectedly, some proximity survives even in fields higher than 1 T. Superconducting states randomly appear and disappear as a function of field and carrier concentration, and each of them exhibits a supercurrent carrying capacity close to the universal quantum limit. We attribute the high-field Josephson effect to mesoscopic Andreev states that persist near graphene edges. Our work reveals new proximity regimes that can be controlled by quantum confinement and cyclotron motion.
AB - Graphene-based Josephson junctions provide a novel platform for studying the proximity effect due to graphene’s unique electronic spectrum and the possibility to tune junction properties by gate voltage. Here we describe graphene junctions with a mean free path of several micrometres, low contact resistance and large supercurrents. Such devices exhibit pronounced Fabry–Pérot oscillations not only in the normal-state resistance but also in the critical current. The proximity effect is mostly suppressed in magnetic fields below 10 mT, showing the conventional Fraunhofer pattern. Unexpectedly, some proximity survives even in fields higher than 1 T. Superconducting states randomly appear and disappear as a function of field and carrier concentration, and each of them exhibits a supercurrent carrying capacity close to the universal quantum limit. We attribute the high-field Josephson effect to mesoscopic Andreev states that persist near graphene edges. Our work reveals new proximity regimes that can be controlled by quantum confinement and cyclotron motion.
U2 - 10.1038/nphys3592
DO - 10.1038/nphys3592
M3 - Letter
VL - 12
SP - 318
EP - 322
JO - Nature Physics
JF - Nature Physics
SN - 1745-2473
IS - 4
ER -