Graphene-based Planar Josephson Junction in Short and Ballistic Regime
ORAL
Abstract
Planar graphene-based Josephson junctions are prepared by the atomic edge contact of two closely arranged Al superconducting electrodes to h-BN encapuslated graphene. We first confirm the ballisticity of our junctions by the Fabry-Perot interference in both the normal and Josephson-coupled states. The IcRN product, a quality factor of Josephson coupling, almost reaches the theoretical limit (~2.4Δ0/e) of the short-and-ballistic Josephson coupling. But the T dependence of the junction Ic does not fit the conventional Kulik-Omel’yanchuk (KO) prediction in the short-and-ballistic regime. No exponentially decaying Ic(T) is observed with increasing temperature near Tc, which excludes the long-junction characteristics. Since the KO model is valid for a one-dimensional point-contact junction it is not relevant to our planar junctions. We confirm that Ic(T) fits well the short-and-ballistic Josephson coupling proposed by a recent theoretical model [1], which takes account of the spatial carrier inhomogeneity in graphene induced by the electronic doping near the superconducting electrodes.
[1] Y. Takane, K.-I. Imura, J. Phys. Soc. Jpn. 81, 094707 (2012).
[1] Y. Takane, K.-I. Imura, J. Phys. Soc. Jpn. 81, 094707 (2012).
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Presenters
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Jinho Park
- POSTECH