Simultaneous perfect polarization of spin and valley using monolayer MoS2 modulated by light and spin Zeeman field

Abstract

Perfect polarization of spin and valley is found to coexist in the proposed junction of monolayer MoS2. 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 , , , and . 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 MoS2 by varying the circularly polarized light and spin Zeeman field. These results demonstrate the modulated monolayer MoS2’s potential as a vital tool in spintronics and valleytronics.