  Ultraflatbands that have been theoretically and experimentally detected in a
bunch of van der Waals stacked materials showing some peculiar properties, for
instance, highly localized electronic states and enhanced electron-electron
interactions. In this Letter, using an accurate tight-binding model, we study
the formation and evolution of ultraflatbands in transition metal
dichalcogenides (TMDCs) under low rotation angles. We find that, unlike in
twisted bilayer graphene, ultraflatbands exist in TMDCs for almost any small
twist angles and their wave function becomes more localized when the rotation
angle decreases. Lattice relaxation, pressure and local deformation can tune
the width of the flatbands, as well as their localization. Furthermore, we
investigate the effect of spin-orbit coupling on the flatbands and discover
spin/orbital/valley locking at the minimum of the conduction band at the K
point of the Brillouin zone. The ultraflatbands found in TMDCs with a range of
rotation angle below $7^\circ$, may provide an ideal platform to study strongly
correlated states.
