Tailoring magnetic insulator proximity effects in graphene: first-principles calculations

Abstract

We report a systematic first-principles investigation of the influence of\ndifferent magnetic insulators on the magnetic proximity effect induced in\ngraphene. Four different magnetic insulators are considered: two ferromagnetic\neuropium chalcogenides namely EuO and EuS and two ferrimagnetic insulators\nyttrium iron garnet (YIG) and cobalt ferrite (CFO). The obtained\nexchange-splitting varies from tens to hundreds of meV. We also find an\nelectron doping induced by YIG and europium chalcogenides substrates, that\nshift the Fermi level up to 0.78 eV and 1.3 eV respectively, whereas hole\ndoping up to 0.5 eV is generated by CFO. Furthermore, we study the variation of\nthe extracted exchange and tight binding parameters as a function of the EuO\nand EuS thicknesses. We show that those parameters are robust to thickness\nvariation such that a single monolayer of magnetic insulator can induce a large\nmagnetic proximity effect on graphene. Those findings pave the way towards\npossible engineering of graphene spin-gating by proximity effect especially in\nview of recent experiments advancement.\n