Berry curvature dipole and nonlinear Hall effect in two-dimensional Nb$_{2n+1}$Si$_n$Te$_{4n+2}$

TL;DR

This study investigates the Berry curvature dipole and nonlinear Hall effect in a family of 2D materials, revealing how their electronic properties vary with composition and suggesting potential for experimental detection.

Contribution

First-principles calculations uncover the composition-dependent Berry curvature dipole and nonlinear Hall response in Nb$_{2n+1}$Si$_n$Te$_{4n+2}$ materials, highlighting a hidden dimensional crossover.

Findings

Pronounced BCD peaks in monolayer Nb$_{3}$SiTe$_{6}$

BCD magnitude decreases with increasing n

Nonlinear Hall response linked to geometric properties

Abstract

Recent experiments have demonstrated interesting physics in a family of two-dimensional (2D) composition-tunable materials Nb$_{2n+1}$Si$_n$Te$_{4n+2}$. Here, we show that owing to its intrinsic low symmetry, metallic nature, tunable composition, and ambient stability, these materials offer a good platform for studying Berry curvature dipole (BCD) and nonlinear Hall effect. Using first-principles calculations, we find that BCD exhibits pronounced peaks in monolayer Nb$_{3}$SiTe$_{6}$ ($n=1$ case). Its magnitude decreases monotonically with $n$ and completely vanishes in the $n\rightarrow\infty$ limit. This variation manifests a special hidden dimensional crossover of the low-energy electronic states in this system. The resulting nonlinear Hall response from BCD in these materials is discussed. Our work reveals pronounced geometric quantities and nonlinear transport physics in Nb$_{2n+1}$Si$_n$Te$_{4n+2}$ family materials, which should be readily detected in experiment.