  Spin splitting bands that arises in conduction band minimum (CBM) of WS2
monolayer (ML) play an important role in the new spin-orbit phenomena such as
spin-valley coupled electronics. However, application of strain strongly
modifies electronic properties of the WS2 ML, which is expected to
significantly affect to the properties of the spin splitting bands. Here, by
using fully-relativistic first-principles calculations based on
density-functional theory, we show that a substantial spin spliting bands
observed in the CBM is effectively controlled and tuned by applying the biaxial
strain. We also find that these spin splitting bands induce spin textures
exhibiting fully out-of-plane spin polarization in the opposite direction
between the K and Q points and their time reversals in the first Brillouin
zone. Our study clarify that the strain plays an significant role in the
spin-orbit coupling of the WS2 ML, which has very important implications in
designing future spintronics devices.
