Fluctuation-induced Neel and Bloch skyrmions at topological insulator surfaces


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Nogueira F. S. , Eremin I., Katmis F., Moodera J. S. , van den Brink J., Kravchuk V. P.

PHYSICAL REVIEW B, cilt.98, 2018 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

Ferromagnets in contact with a topological insulator have become appealing candidates for spintronics due to the presence of Dirac surface states with spin-momentum locking. Because of this, bilayer Bi2Se3-EuS structures, for instance, show a finite magnetization at the interface at temperatures well exceeding the Curie temperature of bulk EuS. Here, we determine theoretically the effective magnetic interactions at a topological insulator-ferromagnet interface above themagnetic ordering temperature. We show that by integrating out the Dirac fermion fluctuations an effective Dzyaloshinskii-Moriya interaction and magnetic charging interaction emerge. As a result, individual magnetic skyrmions and extended skyrmion lattices can form at the interfaces of ferromagnets and topological insulators, the first indications of which have been very recently observed experimentally.