Proximity effects in Graphene and Ferromagnetic CrBr3 van der Waals Heterostructure

TL;DR

This study uses first-principle calculations to explore how a graphene monolayer's magnetic properties are influenced by proximity to a ferromagnetic CrBr3 layer in a van der Waals heterostructure, revealing tunable spin polarization and miniband effects.

Contribution

It demonstrates the magnetic proximity effect in graphene induced by CrBr3 and shows how electric fields can control spin splitting and electronic properties in the heterostructure.

Findings

Spin polarization of graphene up to 63.6%

Miniband splitting of about 73.4 meV

8% enhancement in magnetic moment

Abstract

We report on first-principle calculations on magnetic proximity effect in a van der Waals heterostructure formed by a graphene monolayer induced by its interaction with a two-dimensional (2D) ferromagnet (chromium tribromide, CrBr3). We observe that the magnetic proximity effect arising from the spin-dependent interlayer coupling depends sensitively on the interlayer electronic configuration. The proximity effect results in spin polarization of graphene orbital by up to 63.6 %, together with a miniband splitting band gap of about 73.4 meV and 8% enhancement in magnetic moment (3.47${\mu}$B/cell) in heterostructure. The position of the Fermi level in the Dirac cone is shown to depend strongly on the graphene-CrBr3 interlayer separation of 3.77 Angstrom. Consequently, we also show that a perpendicular electric field can be used to control the miniband spin splitting and transmission spectrum. Also, the interfacial polarization effect due to the existence of two different constituents reinforces the conductivity via electrostatic screening in the heterolayer. These findings point toward potential nanoscale devices where the electric field driven magnetic proximity effect can lead to unique spin controllability and possible engineering of spin gating.