Electrically Controllable Magnetism in Twisted Bilayer Graphene

Luis A. Gonzalez-Arraga, J. L. Lado, Francisco Guinea, Pablo San-Jose

Research output: Contribution to journalArticleScientificpeer-review

62 Citations (Scopus)

Abstract

Twisted graphene bilayers develop highly localized states around AA-stacked regions for small twist angles. We show that interaction effects may induce either an antiferromagnetic or a ferromagnetic (FM) polarization of said regions, depending on the electrical bias between layers. Remarkably, FM-polarized AA regions under bias develop spiral magnetic ordering, with a relative 120° misalignment between neighboring regions due to a frustrated antiferromagnetic exchange. This remarkable spiral magnetism emerges naturally without the need of spin-orbit coupling, and competes with the more conventional lattice-antiferromagnetic instability, which interestingly develops at smaller bias under weaker interactions than in monolayer graphene, due to Fermi velocity suppression. This rich and electrically controllable magnetism could turn twisted bilayer graphene into an ideal system to study frustrated magnetism in two dimensions.

Original languageEnglish
Article number107201
JournalPhysical Review Letters
Volume119
Issue number10
DOIs
Publication statusPublished - 5 Sep 2017
MoE publication typeA1 Journal article-refereed

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