Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electrically controllable magnetism in twisted bilayer graphene   Twisted graphene bilayers develop highly localised states around AA-stacked
regions for small twist angles. We show that interaction effects may induce
either an antiferromagnetic (AF) and a ferromagnetic (F) polarization of said
regions, depending on the electrical bias between layers. Remarkably,
F-polarised AA regions under bias develop spiral magnetic ordering, with a
relative $120^\circ$ misalignment between neighbouring 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, with interesting potential also for a
range of applications.

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The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio