  Twistronics rooted in the twist operation towards bilayer van der Waals
crystals is of both theoretical and technological importance. The realize of
the correlated electronic behaviors under this operation encourages enormous
effort to the research on magic-angle systems which possess sensitive response
to the external field. Here, a giant dielectric difference between 30 plus or
minus degree twist case is observed in a typical magnetic system 2H-VSe2
bilayer. It is shown that due to the structural inversion asymmetry in its
monolayer, the different stacking of the two cases corresponds to the two kind
of valley polarized states: interlayer ferrovalley and interlayer
antiferrovalley. Further investigations reveal that such different dielectric
response between the two states stems from the different Fermi wave vectors
coupled to the electric field. More interestingly, we even obtain the selective
circularly polarized optical absorption by tuning the interlayer twist. These
findings open an appealing route toward functional 2D materials design for
electric and optical devices.
