2D spin transport through graphene-MnBi 2 Te 4 heterojunction.

The development of two-dimensional (2D) magnetic semiconductors promotes the study of nonvolatile control of magnetoelectric nanodevices. MnBi 2 Te 4 is the first realization of antiferromagnetic topological insulator. In semiconductor circuits, metal-semiconductor contacts are usually essential. In future all-carbon circuits, graphene is a promising material for 2D conductive connections. This work studies electronic transport through graphene-MnBi 2 Te 4 -graphene junctions. We find that graphene-MnBi 2 Te 4 interfaces are perfect Ohmic contacts, which benefits the use of MnBi 2 Te 4 in carbon circuits. The currents through MnBi 2 Te 4 junctions possess high spin polarization. Compared with usual van der Waals junctions, lateral graphene-MnBi 2 Te 4 -graphene junctions present a lower barrier and much higher conductance to electrons. These findings may provide guidance for further study of 2D spin filtering.