${\mathrm{ZrTe}}_5$ has recently attracted much attention due to the observation of intriguing nonreciprocal transport responses which necessitate the lack of inversion symmetry ($\mathcal{I}$). However, there has been debate on the exact $\mathcal{I}$-asymmetric structure and the underlying $\mathcal{I}$-breaking mechanism. Here, we report a spontaneous $\mathcal{I}$ breaking in ${\mathrm{ZrTe}}_5$ films, which initiates from interlayer sliding and is stabilized by subtle intralayer distortion. Moreover, we predict significant nonlinear anomalous Hall effect (NAHE) and kinetic magnetoelectric effect (KME), which are attributed to the emergence of Berry curvature and orbital magnetization in the absence of $\mathcal{I}$ symmetry. We also explicitly manifest the direct coupling between sliding ferroelectricity, NAHE, and KME based on a sliding-dependent $k·p$ model. By studying the subsurface sliding in ${\mathrm{ZrTe}}_5$ multilayers, we speculate that surface nonlinear Hall current and magnetization would emerge on the natural cleavage surface. Our findings elucidate the sliding-induced $\mathcal{I}$-broken mechanism in ${\mathrm{ZrTe}}_5$ films and open new avenues for tuning nonreciprocal transport properties in Van der Waals layered materials.

中文翻译：

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拓扑ZrTe5薄膜中自发反演对称性破缺以及贝里曲率和轨道磁化强度的出现


${\mathrm{ZrTe}}_5$ 最近由于观察到有趣的非互易传输响应而引起了广泛关注，该响应需要缺乏反演对称性（ $\mathcal{I}$ ）。然而，对于确切的 $\mathcal{I}$ 不对称结构和潜在的 $\mathcal{I}$ 破坏机制一直存在争议。在这里，我们报告了 ${\mathrm{ZrTe}}_5$ 薄膜中的自发 $\mathcal{I}$ 断裂，该断裂始于层间滑动，并通过微妙的层内变形稳定。此外，我们预测显着的非线性反常霍尔效应（NAHE）和动磁电效应（KME），这归因于在缺乏 $\mathcal{I}$ 对称性的情况下贝里曲率和轨道磁化的出现。我们还基于滑动相关 $k·p$ 模型明确地证明了滑动铁电性、NAHE和KME之间的直接耦合。通过研究 ${\mathrm{ZrTe}}_5$ 多层膜中的次表面滑动，我们推测自然解理表面上会出现表面非线性霍尔电流和磁化强度。我们的研究结果阐明了 ${\mathrm{ZrTe}}_5$ 薄膜中滑动引起的 $\mathcal{I}$ 断裂机制，并为调节范德华层状材料的非互易输运特性开辟了新途径。