Spin-Dependent ππ* Gap in Graphene on a Magnetic Substrate

One of the main challenges in the exploitation of spin injection and transport in graphene is represented by its too-strong electronic interaction with the magnetic contacts. We show by ARPES, spin-ARPES and DFT

calculations, that the intercalation of an Eu monolayer between graphene and Ni restores an almost linear dispersion of the π states.

P. M. Sheverdyaeva et al., Phys. Rev. Lett. 132, 266401 (2024)

 

In correspondence with the Eu 4f binding energy, the spin-degeneracy in graphene is lifted, resulting in the opening of a spin-dependent gap between the π and π^∗ bands at the Dirac point. The energy gap of the bands significantly differs for the two spin channels, a property of potential interest for spin selective injection. Our calculations furthermore suggest the existence of a finite Berry curvature in the vicinity of such gaps. Furthermore, we report on a spectroscopic signature of a polaronic band

and discuss its relation to the van Hove singularity of graphene.