Abstract: Crystalline graphene multilayers present a rich playground to explore correlated electronic phenomena in an ultra-clean setting, free of the inhomogeneities ubiquitous in their twisted counterparts. For instance, Bernal bilayer graphene (BLG) and rhombohedral trilayer graphene both exhibit several symmetry-broken metallic phases at low temperature, as well as superconductors with different pairing symmetries. Moreover, placing a WSe2 monolayer on BLG was shown to promote Cooper pairing to an extraordinary degree, with an order-of-magnitude enhancement of Tc [1]. I will first discuss the lessons learned from our recent Hartree-Fock exploration of the phase diagram of graphene multilayers with induced spin-orbit coupling [2,3], including the appearance of various intervalley coherent orders, and their possible connection to superconductivity. I will then outline a theoretical recipe to engineer topological superconductivity in BLG/WSe2 using gate-defined planar Josephson junctions [4]. Such a platform may hold advantages over traditional architectures to experimentally realize Majorana fermions due its purity, gate tunability and atomically-thin nature.
[1] Y. Zhang, R. Polsi, A. Thomson, ÉLH, et al. Nature 613, 268 (2023).
[2] J. M. Koh, J. Alicea, ÉLH. Phys. Rev. B 109, 035113 (2024).
[3] J. M. Koh, A. Thomson, J. Alicea, ÉLH. In preparation.
[4] Y. Xie, ÉLH, A. Young, S. Nadj-Perge, J. Alicea, Phys. Rev. Lett. 131, 146601 (2023).