Graphene Spintronic: Intercalated boosters

Marko Kralj, News & Views, Nature Physics 11, January 2015

The journal Nature Physics, in its on-line edition for December 2014, published a work of researchers from Spain and Russia (Calleja, F. et al. Nature Phys.http://dx.doi.org/10.1038/nphys3173 ) dealing with the possibility of strong modulation of spin-orbit interaction in graphene by intercalation with lead islands. According to the journal editor’s decision this article deserves particular attention and announcement in the section News & Views of the journal. The latter distinguished task has been accredited to our colleague dr. Marko Kralj, clearly on basis of his own achievements in graphene physics research.

In his New & Views elaboration dr.Kralj points out an intrinsically weak spin-orbit coupling characterizing graphene as a main obstacle in generation of spin-polarized currents, necessary for applications in spintronics. The latter equally applies to the case of spin polarization generated on basis of the intrinsic quantum Hall effect and the related topological edge states. To circumvent this intrinsic problem a possibility of the increased spin-orbit coupling, by the use of extrinsic mechanisms, has been discussed in dr. Kralj’s elaboration of the problem. The most straightforward way to do that would be intercalation of the graphene layer by heavy element atoms/islands, as presented in the subject research article by Calleja et al. Dr. Kralj concludes that a future more advanced spin-orbit engineering will have to include, besides intercalation, control over additional degrees of freedom, like the internal graphene strain.

a) Simple scheme of a spintronic transistor, involving two ferromagnetic electrodes (green, yellow) necessary for generation of spin-polarized current. b) Spin-polarized topological graphene edge states. c) Sketch of the intercalation with lead islands (orange) taken in order to enhance spin-orbit coupling.