Anomalous Phase Dynamics of Driven Graphene Josephson Junctions

Abstract

Josephson junctions with weak-links of exotic materials allow the elucidation of the Josephson effect in previously unexplored regimes. Further, such devices offer a direct probe of novel material properties, for example in the search for Majorana fermions. In this work, we report on DC and AC Josephson effect of high-mobility, hexagonal boron nitride (h-BN) encapsulated graphene Josephson junctions. On the application of RF radiation, we measure phase-locked Shapiro steps. An unexpected bistability between $\pm 1$ steps is observed with switching times on the order of seconds. A critical scaling of a bistable state is measured directly from the switching time, allowing for direct comparison to numerical simulations. We show such intermittent chaotic behavior is a consequence of the nonlinear dynamics of the junction and has a sensitive dependence on the current-phase relation. This work draws connections between nonlinear phenomena in dynamical systems and their implications for ongoing condensed matter experiments exploring topology and exotic physics.

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Cited by in corpus (4)

• Zero-bias crossings and peculiar Shapiro maps in graphene Josephson junctions
• Probing Topological Superconductivity of oxide nanojunctions using fractional Shapiro steps
• Hysteresis and chaos in anomalous Josephson junctions without capacitance
• Anisotropic supercurrent suppression and revivals in a graphene-based Josephson junction under in-plane magnetic fields