Yao-Jui Chan, Syed Mohammed Faizanuddin, Raju Kalaivanan, Sankar Raman, Hsin Lin, Uddipta Kar, Akhilesh Kr. Singh, Wei-Li Lee, Ranganayakulu K. Vankayala, Min-Nan Ou, Yu-Chieh Wen
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引用次数: 0
Abstract
Spectroscopic identification of distinct nonlinear photocurrents unveils
quantum geometric properties of electron wavefunctions and the momentum-space
topological structures. This is especially interesting, but still puzzling, for
chiral topological semimetals with possibilities of hosting giant quantized
circular photogalvanic effect. Here we report a comprehensive terahertz (THz)
emission spectroscopic analysis of nonlinear photoconductivity of chiral
multifold CoSi at 0.26 ~ 1 eV. We find a large linear shift conductivity (17
{\mu}A/V2), and confirm a giant injection conductivity (167 {\mu}A/V2) as a
consequence of strongly interfered non-quantized contributions from the
vicinity of multifold nodes with opposite chiralities. The bulk injection
current excited by the pump field with a complex wavevector is shown to carry
both longitudinal and transverse components. Symmetry analyses further unveil
weak nonlocal photon drag effect in addition to the photogalvanic effect. This
work not only highlights chiral transition metal monosilicides for mid-infrared
photovoltaic applications via various nonlinear optical channels, but also
consolidates the THz spectroscopy for quantitative photovoltaic research.
对不同非线性光电流的光谱鉴定揭示了电子波函数和动量拓扑结构的量子几何特性。这对于手性拓扑半金属来说尤其有趣,但仍然令人费解,因为手性拓扑半金属有可能承载巨大的量子化环形光电效应。在此,我们报告了在 0.26 ~ 1 eV 波长下对手性拓扑 CoSi 的非线性光电导性进行的全面太赫兹(THz)发射光谱分析。我们发现了巨大的线性偏移电导率(17{\mu}A/V2),并证实了巨大的注入电导率(167{\mu}A/V2),这是来自具有相反手性的多折节点的强干扰非量化贡献的结果。由泵场激发的具有复杂波矢量的体注入电流同时携带纵向和横向分量。对称性分析进一步揭示了除了光电效应之外的弱非局部光子拖曳效应。这项工作不仅强调了手性过渡金属单硅化物通过各种非线性光学通道在中红外光电领域的应用,而且巩固了太赫兹光谱学在定量光电研究中的地位。