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arXiv 2408.04017cond-mat.mes-hallcond-mat.mtrl-sciphysics.opticsquant-ph
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拓扑极化织构中的位移光电流涡旋

Shift photocurrent vortices from topological polarization textures

Aneesh Agarwal, Wojciech J. Jankowski, Daniel Bennett, Robert-Jan Slager

AI总结:

本文提出通过非线性光学响应探测扭曲双层vdW铁电体中的拓扑极化织构,发现位移光电流形成实空间涡旋,且与极化场反平行,为实验观测提供了新策略。

摘要:

继范德华(vdW)铁电体近期受到关注后,理论上预测在扭曲双层中会形成拓扑非平凡的极性结构。然而,这些结构在实验上难以观测。我们提出,这些织构可以通过光学手段探测,因为拓扑极化织构会导致奇异的非线性光学响应。我们利用非阿贝尔Berry联络和量子几何框架解析推导了这一关系,并辅以紧束缚和第一性原理计算。对于无中心对称的莫尔材料,其形成极性meron和antimeron网络,位移光电导在实空间中形成涡旋状结构。在布里渊区边缘发生拓扑平凡带间跃迁的频率范围内,位移光电流与面内电子极化场反平行。我们的发现凸显了vdW材料中复杂极化织构与非线性光学响应之间的相互作用,并为其实验探测提供了一种亟需的策略。

英文摘要:

Following the recent interest in van der Waals (vdW) ferroelectrics, topologically nontrivial polar structures have been predicted to form in twisted bilayers. However, these structures have proven difficult to observe experimentally. We propose that these textures may be probed optically by showing that topological polarization textures result in exotic nonlinear optical responses. We derive this relationship analytically using non-Abelian Berry connections and a quantum-geometric framework, supported by tight-binding and first-principles calculations. For the case of moiré materials without centrosymmetry, which form networks of polar merons and antimerons, the shift photoconductivity forms a vortex-like structure in real space. For a range of frequencies where transitions between topologically trivial bands occur at the Brillouin zone edge, the shift photocurrents are antiparallel to the in-plane electronic polarization field. Our findings highlight the interplay between complex polarization textures and nonlinear optical responses in vdW materials and provide a sought-after strategy for their experimental detection.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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