标题： 1$T$-VSe$_2$纳米片中电荷密度波调制的三阶非线性霍尔效应 显示英文标题

标题： Charge density wave modulated third-order nonlinear Hall effect in 1$T$-VSe$_2$ nanosheets

摘要： 我们报告在1$T$相VSe$_2$纳米片中观察到显著的三阶非线性霍尔效应（NLHE），该纳米片通过化学气相沉积（CVD）合成。这些纳米片在$\sim$77 K时表现出电荷密度波（CDW）转变。详细的角分辨和温度依赖测量显示，三阶谐波霍尔电压$V_{3\omega}^\perp$与偏置电流$I_\omega$之间存在强烈的立方关系，这种关系一直持续到室温。值得注意的是，三阶NLHE表现出双倍角度依赖性，并在CDW转变温度以下显著增强，表明CDW相中存在三重对称性破缺。标度分析表明，在CDW相中，来自贝里连接极化率张量的本征贡献显著增加，而在较高温度下，外部效应占主导地位。我们的发现突显了CDW诱导的对称性破缺在调节VSe$_2$的量子几何特性及非线性输运现象中的关键作用，为未来在低维量子材料中的探索铺平了道路。 显示英文摘要

摘要： We report the observation of a pronounced third-order nonlinear Hall effect (NLHE) in 1$T$-phase VSe$_2$ nanosheets, synthesized using chemical vapor deposition (CVD). The nanosheets exhibit a charge density wave (CDW) transition at $\sim$77 K. Detailed angle-resolved and temperature-dependent measurements reveal a strong cubic relationship between the third-harmonic Hall voltage $V_{3\omega}^\perp$ and the bias current $I_\omega$, persisting up to room temperature. Notably, the third-order NLHE demonstrates a twofold angular dependence and significant enhancement below the CDW transition temperature, indicative of threefold symmetry breaking in the CDW phase. Scaling analysis suggests that the intrinsic contribution from the Berry connection polarizability tensor is substantially increased in the CDW phase, while extrinsic effects dominate at higher temperatures. Our findings highlight the critical role of CDW-induced symmetry breaking in modulating quantum geometric properties and nonlinear transport phenomena in VSe$_2$, paving the way for future explorations in low-dimensional quantum materials.