  Localization of charge carriers in monolayers (MLs) of transition metal
dichalcogenides (TMDs) dramatically increases spin and valley coherence times,
and, by analogy with other systems, the role of the hyperfine interaction
should enhance. We perform theoretical analysis of the intervalley hyperfine
interaction in TMD MLs based on the group representation theory. We
demonstrate, that the spin-valley locking leads to the helical structure of the
in-plane hyperfine interaction. In the upper valence band the hyperfine
interaction is shown to be of the Ising type, which can be used for fabrication
of the atomically thin quantum dots with the long spin and valley coherence
times.
