Probing Tunneling Magnetoresistances in Chromium Trihalide Junctions via First Principles Calculations

The demonstration of magnetic tunnel junctions in heterostructures formed with two-dimensional materials has spawned research ventures regarding spin transport in these layered systems. Efforts that initiated with CrI₃ have now been expanded to other chromium trihalides such as CrBr₃ and CrCl₃. Owing to their nanometer thicknesses, the electronic and magnetic properties of chromium trihalide systems are affected by quantum confinement effects along with their environments. Here we characterize physical properties of multilayer chromium trihalide/graphene junctions using density functional theory (DFT) and Landauer’s formalism for ballistic transport. We find that band alignments in few-layer chromium trihalide (CrX₃ with X = F, Cl, Br and I) slabs change based on the metamagnetic state of the junctions and differ from those of isolated layers. We also delve into metamagnetic dependent complex band structures as well as discuss changes in the band structures of chromium trihalide junctions beyond DFT. Our results suggest that tunneling magnetoresistance values as high as 4,000% can be attained in bilayer heterojunctions.