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Quantum Candidate Talk
February 22 | 4:00 pm - 5:00 pm
Title: Superconducting electronics with graphene heterostructures
Abstract: Heterostructures of graphene and boron nitride offer unique opportunities for superconducting
electronics because of their ballistic transport properties and highly transparent edge-contacts. They provide a convenient medium to develop devices where superconductivity coexists with other electronic phases, or to engineer more complex junctions where multiple superconducting electrodes are strongly coupled through the same graphene channel.
Multiterminal junctions, in particular, are appealing because the increased complexity of their superconducting phase space results in a variety of nonlinear dynamics phenomena, which presents opportunities for novel device functionalities. Moreover, it was recently proposed that driven multiterminal junctions could be used to engineer Floquet states, and that the phase-dependent energy spectrum of their bound-states could yield insights into topological materials.
In this talk, I will discuss the transport properties of graphene-based multiterminal junctions driven out-of-equilibrium. I will first describe how to control the different superconducting pathways through these devices, and how they can be used as highly-tunable and efficient superconducting triodes, where a supercurrent may only flow in one direction. I will then show
how phase synchronization effects can result in stable supercurrents even at finite voltage biases. Finally, we will discuss the inverse AC Josephson effect in multiterminal junctions, and see how competing phase-locked states result in fractional Shapiro voltage steps.
Host: Vladimir Skokov