AI 中文总结
研究低维半金属中室温本征非线性热电效应，利用梯度反转技术谐波检测，在$T_\mathrm{d}$-WTe$_2$和TaIrTe$_4$中实现，解析二阶热电张量分量，证明相关贡献支配响应，为探索高阶热到电荷电流转换提供平台。
AI 中文摘要
热电响应的非互易控制为下一代热管理和能量转换提供了一个有前景的策略。虽然非线性电输运最近已成为低对称量子材料的一种本征特性，但其热电对应物尚未得到证实。在此，利用梯度反转技术的谐波检测，我们报告了在无磁场或磁性材料的情况下，低对称II型外尔半金属$T_\mathrm{d}$-WTe$_2$和TaIrTe$_4$中高达室温的本征非线性热电响应。我们解析了二阶热电张量的所有对称允许分量，包括非线性塞贝克、非线性能斯特和非线性混合方向热电效应，并证明与贝里曲率相关和散射诱导的贡献都支配着不同的非线性热电响应。我们的结果表明，非线性热电性本质上源于晶体对称性的降低，并且与这些材料中的散射相关的工程效应为探索超越线性响应的高阶热到电荷电流转换提供了一个通用平台。
英文摘要
Nonreciprocal control of thermoelectric responses offers a promising strategy for next-generation thermal-management and energy-conversion. While nonlinear electrical transport has recently emerged as an intrinsic property of low-symmetry quantum materials, their thermoelectric counterparts have not been demonstrated. Here, exploiting harmonic detection with gradient-reversal techniques, we report intrinsic nonlinear thermoelectric responses up to room temperature in the low-symmetry type-II Weyl semimetals $T_\mathrm{d}$-WTe$_2$ and TaIrTe$_4$ in the absence of magnetic fields or magnetic materials. We resolve all symmetry-allowed components of the second-order thermoelectric tensor, including the nonlinear Seebeck, nonlinear Nernst, and nonlinear mixed-directional thermoelectric effects and demonstrate that both Berry-curvature-related and scattering-induced contributions govern the different nonlinear thermoelectric responses. Our results show that nonlinear thermoelectricity arises intrinsically from reduced crystal symmetry and that engineering effects related to scattering in these materials provides a versatile platform for exploring higher-order heat-to-charge current conversion beyond the linear response.
Comments37 pages, 24 figures
