Ferromagnetic CrBr$_3$-Induced Graphene Spintronics

Abstract

Our proposed spin valve prototype showcases a sophisticated design featuring a two-dimensional graphene bilayer positioned between layers of ${CrBr}_3$ ferromagnetic insulators. In this model, proximity coupling plays a pivotal role, influencing the magnetization orientations of the graphene layers and significantly impacting the \textit{in-plane} conductivity of the ${CrBr}_3$ layers. In this present work, we position the graphene bilayer between two layers of the ferromagnetic insulator ${CrBr}_3$ to establish this configuration. Using density functional theory, we conduct detailed computations to analyze the electronic structure of this sandwiched system. Our findings reveal a notable finite gap at specific \textit{k}-points, particularly evident in the antiparallel configuration of the magnetizations. This finding represents a significant advancement in spintronics, underscoring the potential of our spin valve prototype to drive innovation in electronic device technologies.

Figures (4)

• Figure 1: (a) Atomic structure of a CrBr$_3$-BLG-CrBr$_3$ heterostructure unit cell. Inter-planner spacing notation of the structure in (b) and molecular surface formation of the heterostructure showing distribution (c). Atomic structure of a CrBr$_3$-graphene bilayer-CrBr$_3$ heterostructure supercell of 5*5*1 (d). Polyhedra presentation of the same heterostructure showing the electron bond and distribution (e).
• Figure 2: DFT band structure of the heterostructure with inset showing finite gap opening of 56.87 meV. Blue colour and red colour dotted lines present both majority and minority spins of both systems, respectively along highly symmetric k-points.
• Figure 3: DFT calculation results in bilayer graphene sandwiched by CrBr$_3$. (a) The energy difference between ferromagnetic and antiferromagnetic states. (b) Spin-dependent gap as a function of U in presence of field.
• Figure 4: DFT local potential distribution of the CrBr$_3$-BLG-CrBr$_3$ heterostructure with contribution from both CrBr$_3$ monolayer and graphene bilayer along z-direction.