Abstract
We report a systematic first-principles investigation of the influence of different magnetic insulators on the magnetic proximity effect induced in graphene. Four different magnetic insulators are considered: two ferromagnetic europium chalcogenides namely EuO and EuS and two ferrimagnetic insulators yttrium iron garnet (YIG) and cobalt ferrite (CFO). The obtained exchange-splitting in graphene varies from tens to hundreds of meV depending on substrates. We find an electron doping to graphene induced by YIG and europium chalcogenides substrates, that shift the Fermi level above the Dirac cone up to 0.78 eV and 1.3 eV respectively, whereas hole doping shifts the Fermi level down below the Dirac cone about 0.5 eV in graphene/CFO. Furthermore, we study the variation of the extracted exchange and tight-binding parameters as a function of the EuO and EuS thicknesses. We show that those parameters are robust to thickness variation such that a single monolayer of magnetic insulator can induce a strong magnetic proximity effect on graphene. Those findings pave the way towards possible engineering of graphene spin-gating by proximity effect especially in view of recent experimental advancements.
Highlights
Graphene spintronics is one of the most promising directions of innovation for twodimensional materials, opening new prospects for information technologies [1, 2]
These findings pave the way towards possible engineering of graphene spin-gating by proximity effect especially in view of aforementioned recent experiments on europium sulfite (EuS) and yttrium iron garnet (YIG) on top of graphene
The Vienna ab initio simulation package (VASP) [42, 43, 44] is used for structure optimization, where the electron-core interactions are described by the projector augmented wave method for the potentials [45], and the exchange correlation energy is calculated within the generalized gradient approximation (GGA) of the Perdew-BurkeErnzerhof form [46, 47]
Summary
Graphene spintronics is one of the most promising directions of innovation for twodimensional materials, opening new prospects for information technologies [1, 2]. Prior theoretical study of proximity effects of a ferromagnetic insulator (EuO) on graphene reported a large spin polarization of p orbitals together with a large exchange-splitting band gap [35]. We report systematic studies of electronic band structure of graphene as a function of EuO and EuS thickness where we show that the exchange-splitting gaps are robust to MI thickness variation. These findings pave the way towards possible engineering of graphene spin-gating by proximity effect especially in view of aforementioned recent experiments on EuS and YIG on top of graphene
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call