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| Main Authors: | , , , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2403.09950 |
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Table of Contents:
- We report on the charge dynamics of kagome FeGe, an antiferromagnet with a charge density wave (CDW) transition at $T_{\mathrm{CDW}} \simeq 105$ K, using polarized infrared spectroscopy and band structure calculations. We reveal pronounced optical anisotropy along the $a$- and $c$-axis, as well as an unusual response associated with three-dimensional CDW order. Above $T_{\mathrm{CDW}}$, there is a notable transfer of spectral weight (SW) from high to low energies, promoted by the magnetic splitting-induced shift in bands. Across the CDW transition, we observe a sudden SW transfer from low to high energies over a broad range, along with the emergence of new excitations around 1200 cm$^{-1}$. These results contrast with observations from other kagome metals like CsV$_3$Sb$_5$, where the nesting of VHSs leads to a clear CDW gap feature. Instead, our findings can be accounted for by a $2\times2\times2$ CDW ground state driven by a first-order structural transition involving large partial Ge1-dimerization. Our study thus unveils a complex interplay among structure, magnetism, and charge order, offering valuable insights for a comprehensive understanding of CDW order in FeGe.