AI 中文总结
研究二维碲烯中太赫兹场驱动的二阶非线性电子输运现象，包括NLHE等。通过研究太赫兹辐射激发的直流电流，发现电流与电场平方成正比且依赖方向，由多种贡献组合而成，建立了相关等效性，揭示了电流变化规律及源于微观机制。
AI 中文摘要
我们研究了太赫兹场驱动的二维碲烯薄片中的二阶非线性电子输运现象，包括非线性霍尔效应（NLHE）。研究了沿碲烯c轴方向及垂直于该方向的霍尔条形样品中线性偏振太赫兹辐射激发的直流电流。如二阶输运现象预期，电流与辐射面内电场E的平方成正比且依赖于其方向。电流由NLHE、非线性纵向（NLL）和非线性对角（NLD）电流三种贡献组合而成。我们建立了NLH、NLL和NLD输运电流与线性偏振和非偏振太赫兹辐射吸收引起的线性光电流效应（LPGE）贡献之间的等效性。所有贡献可由栅极电压控制，且电子和空穴电导率符号相反。样品从室温冷却到4.2K时电流大幅增加，且随辐射频率降低而增加。这些结果由所发展的唯象和微观理论很好地描述。我们表明太赫兹辐射诱导的电流源于微观机制，如斜散射、侧跳和贝里曲率偶极子。
英文摘要
We study terahertz field-driven second-order nonlinear electron transport phenomena, including the nonlinear Hall effect (NLHE), in two-dimensional tellurene flakes. The dc current excited by linearly polarized terahertz (THz) radiation in Hall bar samples is investigated in directions both along and perpendicular to the $c$-axis of tellurene. As expected for second-order transport phenomena, the current scales as the square of the in-plane electric field of the radiation $\bf E$, and depends on its orientation. The current results from a combination of three contributions, including the NLHE, the Nonlinear Longitudinal (NLL) and Nonlinear Diagonal (NLD) currents. We established the equivalence between NLH, NLL, and NLD transport currents and Linear photogalvanic effect (LPGE) contributions induced by the absorption of linearly polarized and unpolarized THz radiation. All contributions can be controlled by a gate voltage and have opposite signs for electron and hole conductivity. The magnitude of the current increases drastically when the samples are cooled from room temperature to 4.2 K. It also increases with decreasing radiation frequency. These results are well described by the developed phenomenological and microscopic theories. We show that the THz radiation-induced electric current originates from microscopic mechanisms such as skew scattering, side jump, and the Berry curvature dipole.
Comments13 pages, 9 figures
