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Electrically Controllable Magnetism in Twisted Bilayer Graphene.
- Source :
-
Physical review letters [Phys Rev Lett] 2017 Sep 08; Vol. 119 (10), pp. 107201. Date of Electronic Publication: 2017 Sep 05. - Publication Year :
- 2017
-
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.
Details
- Language :
- English
- ISSN :
- 1079-7114
- Volume :
- 119
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Physical review letters
- Publication Type :
- Academic Journal
- Accession number :
- 28949176
- Full Text :
- https://doi.org/10.1103/PhysRevLett.119.107201