  The Kekule pattern of the (anti)ferromagnetic exchange field on monolayer
MoS2 can be induced by proximity to the (111) surface of BiFeO3 on both sides.
The three-band tight binding model of the MoS2 layer with Kekule patterned
exchange field is applied to describe the heterostructures. The tight binding
model is justified by the first principle calculations. The magnetization
orientations of the substrates control the pattern of the exchange field, which
then switches the band structures of the lowest zigzag edge states between
being metallic and insulating. The lowest four zigzag edge bands provide
conducting channels with a spin-polarized current. Optical excitation of
carriers in these bands generates sizable spin and charge currents, which are
theoretically modeled by the perturbation solution of the semiconductor Bloch
equation. The injected spin currents have multiple resonant peaks at a few
frequencies, which can be switched off by rotating the magnetization
orientations of the substrates.
