Valley- and spin-filter in monolayer MoS2

• A normal/ferromagnetic/normal molybdenum disulfide junction is investigated.
• The charge current through the system shows fully valley-and spin polarizations.
• The polarization can be inverted by reserving the direction of the exchange field in the ferromagnetic region.
• The valley- and spin polarizations are discussed in this system.
• The polarization has important implications in the valleytronic and spintronic fields.

We propose a valley- and spin-filter based on a normal/ferromagnetic/normal molybdenum disulfide (MoS2) junction where the polarizations of the valley and the spin can be inverted by reversing the direction of the exchange field in the ferromagnetic region. By using a modified Dirac Hamiltonian and the scattering formalism, we find that the polarizations can be tuned by applying a gate voltage and changing the exchange field in the structure. We further demonstrate that the presence of a topological term (β) in the Hamiltonian results in an enhancement or a reduction of the charge conductance depending on the value of the exchange field.