  In a system with inversion symmetry broken, a second-order nonlinear Hall
effect can survive even in the presence of time-reversal symmetry. In this
work, we show that a giant nonlinear Hall effect can exist in twisted bilayer
WTe2 system. The Berry curvature dipole of twisted bilayer WTe2 ({\theta} =
29.4{\deg}) can reach up to ~1400 {\AA}, which is much larger than that in
previously reported nonlinear Hall systems. In twisted bilayer WTe2 system,
there exists abundant band anticrossings and band inversions around the Fermi
level, which brings a complicated distribution of Berry curvature, and leading
to the nonlinear Hall signals exhibit dramatically oscillating behavior in this
system. Its large amplitude and high tunability indicate that the twisted
bilayer WTe2 can be an excellent platform for studying the nonlinear Hall
effect.
