Macroscopic CVD Graphene for Nano-electronics : from growth to proximity-induced 2D superconductivity

Orateur : Soutenance de thèse de Zheng HAN (Institut Néel)

Graphene is an attractive platform to study superconductivity in 2D. Its exposed and inert surface allows the intimate coupling of superconductors, giving rise to superconducting proximity effect. At the same time, gate-tunability of the electron density opens the possibility to study the stability of the superconducting phase against quantum fluctuations in 2D. Recently, rapid development in chemical vapor deposited (CVD) graphene expands the application of graphene into macro-scale and batch fabrication. In this presentation, we will first show a novel CVD method, in which precursors are injected in a pulsed-manner to eliminate parasitic multi-layers formation. In the second part, we will focus on a model system, in which CVD graphene is dressed with a superconducting ordered triangle array. In such a proximately-coupled superconducting array, quantum fluctuation induced break-down of superconductivity was seen by tuning the gate voltage at very low temperature. This superconductor-to-metal quantum phase transition is in good agreement with recent theoretical works.

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