Hyperfine interaction in atomically thin transition metal dichalcogenides
The spin dynamics of the localized charge carriers is mainly driven by the hyperfine interaction with the nuclear spins. Here we develop a theory of the hyperfine interaction in transition metal dichalcogenides monolayers. Using the group representation theory and tight binding model we derive effective Hamiltonians of the intervalley hyperfine interaction in the conduction and valence bands. The spin-valley locking and pronounced spin-orbit splitting lead to the specific form of the hyperfine interaction, which we call ``helical''. We also demonstrate, that the hyperfine interaction is noncollinear for chalcogen atoms in general case. In the same time in the upper valence band the hyperfine interaction is purely of the Ising type, which suggests, that the spin-valley polarization of localized holes in transition metal dichalcogenides monolayers can be conserved for particularly long time.