# Band signatures for strong nonlinear Hall effect in bilayer WTe$_2$

## TL;DR

This paper investigates the origins of the nonlinear Hall effect in bilayer WTe$_2$, linking strong signals to specific band-structure features like tilted anticrossings and inversions, advancing understanding of emergent material responses.

## Contribution

It reveals the band-structure signatures associated with strong nonlinear Hall signals in 2D WTe$_2$, providing a theoretical framework for analyzing nonlinear Hall effects in low-symmetry materials.

## Key findings

- Nonlinear Hall signals are prominent near tilted band anticrossings.
- Band inversions are linked to strong nonlinear Hall responses.
- The study explains experimental observations in 2D WTe$_2$.

## Abstract

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. Low-symmetry two-dimensional materials are promising candidates for the nonlinear Hall effect, but it is less 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. These band signatures can be used to explain the strong nonlinear Hall effect in the recent experiments on two-dimensional WTe$_{2}$. This Letter will be instructive not only for analyzing the transport signatures of the nonlinear Hall effect but also for exploring unconventional responses in emergent materials.