Majorana Zero Modes in Graphene

Ramón Aguado, ICMM-CSIC

In this talk, I will discuss a novel approach to obtain topological superconductivity and Majorana states in graphene-superconductor junctions without the need for spin-orbit coupling [1]. Key to our proposal is the interaction-induced magnetic ordering of graphene’s zero Landau level (ZLL). Coupling this unique state to an s-wave superconductor gives rise to novel edge states whose properties depend on the type of magnetic order. In particular, the canted antiferromagnetic phase is a natural host for Majorana bound states. Our proposal combines effects that were recently demonstrated experimentally (tunable spin ordering of the ZLL [2] and ballistic graphene-superconductor junctions of high transparency [3] operating in the quantum Hall regime [4]) and is thus ready to be tested.

[1] P. San Jose, J. L. Lado, R. Aguado, F. Guinea, and J. Fernández-Rossier, PHYSICAL REVIEW X 5, 041042 (2015).
[2] A. F. Young, et al, Nature (London) 505, 528 (2014).
[3] M. Ben Shalom, et al, Nature Physics 12, 318–322 (2016).
[4] V. E. Calado, et al, Nat. Nanotechnol. 10, 761 (2015).