Analysis of Magnetoresistance in CrI₃-graphene Heterostructures via First-principles Calculations

Recently, spin transport was demonstrated in heterostructures based on two-dimensional (2D) materials. Here we characterize electronic transport through multilayer CrI₃ systems (bilayer, trilayer, and tetralayer) using the density functional theory (DFT) and the Landauer formalism for ballistic transport. Electronic structure of these tunneling junctions reveal that the interplay of quantum confinement and metamagnetic configurations defines the different tunneling rates. Hence, atomistic calculations capturing coupling between layers are key to these descriptions. Our ballistic transport calculations are in agreement with recent experimental measurements of magnetoresistance in graphene/CrI₃/graphene [Klein et al., Science 360, 1218 (2018)]. We apply our transport studies for this type of tunneling junction to other metallic leads with Fermi level density of states larger than that of graphene and compare to other Cr halides junctions. While tunneling resistivity is significantly reduced, magnetoresistance ratios do not necessarily increase due to the intricate complex band structure of these systems. The atomistic details provided by this work may prove valuable towards the use of these 2D material-based spintronic devices.