Nonlinear Hall effect

Unconventional responses upon breaking discrete or crystal symmetries open avenues for exploring emergent physical systems and materials. By breaking inversion symmetry, a nonlinear Hall signal can be observed, even in the presence of time-reversal symmetry, quite different from the conventional Hall effects. However, less is known when a strong nonlinear Hall signal can be measured, in particular, its connections with the band-structure properties. By using model analysis, we find prominent nonlinear Hall signals near tilted band anticrossings and band inversions [1]. These band signatures can be used to explain the strong nonlinear Hall effect in the recent experiments on two-dimensional WTe2 [2]. Disorder plays indispensable roles in various linear Hall effects. We derive the formulas of the nonlinear Hall conductivity in the presence of disorder scattering and construct the general scaling law of the nonlinear Hall effect, which may help in experiments to distinguish disorder-induced contributions to the nonlinear Hall effect [3].