Spin and valley dependent transport and tunneling magnetoresistance in irradiated ferromagnetic WSe2double barrier junctions
摘要
Spin and valley polarizations (Ps and PKK’) 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 PKK’ = -1 or Ps = 1 is wider (narrower) and increases with ΔΩ. As h increases, the Ps = 1 (PKK’ = -1 or Ps = 1) plateau becomes wider (narrower) for the P (AP) configuration. As U increases, the energy region with PKK’ = -1 increases first and then moves parallel to the EF-axis, and the energy region with Ps = 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.