Séminaire IQ/RQMP : Étienne Lantagne-Hurtubise
Date : 6 octobre 2022 13:30
Type : Institut Quantique
Enhanced superconductivity in spin-orbit proximitized Bernalbilayer graphene
Crystalline graphenemultilayers present a promising platform to explore correlated electronicphenomena in an ultra-clean setting free of the inhomogeneities ubiquitous inmoiré systems. For instance, Bernal-stacked bilayer graphene (BLG) in a strongperpendicular electric field exhibits several symmetry-broken metallic phasesand a fragile, magnetic-field induced superconducting phase with a criticaltemperature Tc ~ 30 mK . I will first discuss the experimental discovery that placing monolayer WSe2 on BLG promotes Cooper pairing to an extraordinary degree:superconductivity appears at zero magnetic field with an order-of-magnitudeenhancement of Tc to ~300 mK. Quantum oscillations show that superconductivityarises from spin-valley polarized Fermi surfaces, while in-plane magnetic fieldmeasurements reveal a Pauli limit violation that can be continuously tuned withdoping. I will then describe theoretical work suggesting plausible mechanismsfor the enhancement of pairing by WSe2, and show how competitionbetween proximity-induced spin-orbit couplings and orbital effects can accountfor the doping dependence of the Pauli limit violation. These results pave theway for engineering robust, tunable and ultra-clean graphene-basedsuperconductors.
 Isospin magnetism and spin-polarizedsuperconductivity in Bernal bilayer graphene, H. Zhou, L. Holleis, Y. Saito, L. Cohen, W. Huynh, C. L. Patterson,F. Yang, T. Taniguchi, K. Watanabe, A. F. Young. Science 375(2021)
 Enhancedsuperconductivity in spin-orbit proximitized Bernal bilayer graphene, Y. Zhang, R.Polski, A. Thomson, ÉLH, C. Lewandowski, H. Zhou, K. Watanabe, T.Taniguchi, J. Alicea, and S. Nadj-Perge, arXiv:2205.05087.