Giant Nonlinear Hall Effect in Twisted Bilayer WTe2

Understand

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.