Role of quantum confinement and interlayer coupling in CrI3-graphene magnetic tunnel junctions

Recent demonstrations of magnetic ordering and spin transport in\ntwo-dimensional heterostructures have opened research venues in these material\nsystems. In order to control and enhance the related physical phenomena,\nquantitative descriptions linking experimental observations to atomic details\nmust be produced. Here we combine first principles and quantum ballistic\ntransport calculations to shed important insights from an atomistic viewpoint\non the underlying mechanisms governing spin transport in graphene/CrI$_3$\njunctions. Descriptions of the electronic structure reveal that tunneling is\nthe dominant transport mechanism in these heterostructures and help\ndifferentiate intermediate metamagnetic states present in the switching\nprocess. We find that quantum confinement and layer-layer interactions are key\nto describing transport in these two-dimensional systems. Ballistic transport\ncalculations further support these findings and yield magnetoresistance values\nin remarkable agreement with experiments. The short width of these barriers\nlimits analysis solely based on the bulk complex band structure often employed\nin the description of magnetic tunnel junctions. Our work devises mechanisms to\nattain larger tunneling magnetoresistances, proving valuable to the advancement\nof spin valves in layered heterostructures.\n