Spin and valley dependent transport and tunneling magnetoresistance in irradiated ferromagnetic WSe₂double barrier...

Spin and valley polarizations (P_s and P_KK') and tunneling magnetoresistance (TMR) are demonstrated in the ferromagnetic/barrier/normal/barrier/ferromagnetic WSe₂ junction, with the gate voltage and off-resonant circularly polarized light (CPL) applied to the two barrier regions. The minimum incident energy of non-zero spin- and valley-resolved conductance has been derived, which is consistent with numerical calculations and depends on the electric potential U, CPL intensity ΔΩ, exchange field h, and magnetization configuration: parallel (P) or antiparallel (AP). For the P (AP) configuration, the energy region with P_KK' = -1 or P_s = 1 is wider (narrower) and increases with ΔΩ. As h increases, the P_s = 1 (P_KK' = -1 or P_s = 1) plateau becomes wider (narrower) for the P (AP) configuration. As U increases, the energy region with P_KK' = -1 increases first and then moves parallel to the E_F-axis, and the energy region with P_s = 1 for the P configuration remains unchanged first and then decreases. The energy region for TMR = 1 increases rapidly with h, remains unchanged first and then decreases as U increases, and has little dependence on ΔΩ. When the helicity of the CPL reverses, the valley polarization will switch. This work sheds light on the design of spin-valley and TMR devices based on ferromagnetic WSe₂ double-barrier junctions.