Simultaneous perfect polarization of spin and valley using monolayer MoS 2 modulated by light and spin Zeeman field

Perfect polarization of spin and valley is found to coexist in the proposed junction of monolayer MoS 2 . The junction consists of two barriers modulated by off-resonant circularly polarized light and spin Zeeman field, respectively. By appropriately altering the modulation, we can achieve all four combinations of simultaneous perfect spin and valley polarization, which are K ↑ , K ↓ , K ′ ↑ , and K ′ ↓ . Moreover, we have found that by continuously tuning the light illuminating the junction, the valley polarization will abruptly dive from 100% to −100%. The spin polarization exhibits similar features when we tune the spin Zeeman field. Thus, the valley switching effect and the spin switching effect are realized in monolayer MoS 2 by varying the circularly polarized light and spin Zeeman field. These results demonstrate the modulated monolayer MoS 2 ’s potential as a vital tool in spintronics and valleytronics.