Coherent phonon and unconventional carriers in the magnetic kagome metal Fe$_3$Sn$_2$
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866913715645841408 |
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| author | Gonçalves-Faria, M. V. Pashkin, A. Wang, Q. Lei, H. C. Winnerl, S. Tsirlin, A. A. Helm, M. Uykur, E. |
| author_facet | Gonçalves-Faria, M. V. Pashkin, A. Wang, Q. Lei, H. C. Winnerl, S. Tsirlin, A. A. Helm, M. Uykur, E. |
| contents | Temperature- and fluence-dependent carrier dynamics of the magnetic Kagome metal Fe$_3$Sn$_2$ were studied using the ultrafast optical pump-probe technique. Two carrier relaxation processes ($τ_1$ and $τ_2$) and a laser induced coherent optical phonon were observed. By using the two-temperature model for metals, we ascribe the shorter relaxation $τ_1$ (~1 ps) to hot electrons transferring their energy to the crystal lattice via electron-phonon scattering. $τ_2$ (~25 ps), on the other hand, cannot be explained as a conventional process and is attributed to the unconventional (localized) carriers in the material. The observed coherent oscillation is assigned to be a totally symmetric A$_{1g}$ optical phonon dominated by Sn displacements out of the Kagome planes, and possesses a prominently large amplitude, on the order of 10$^{-3}$, comparable to the maximum of the reflectivity change ($Δ$R/R). This amplitude is equivalent to charge-density-wave (CDW) systems, although no signs of such an instability were hitherto reported in Fe$_3$Sn$_2$. Our results set an unexpected connection between Fe$_3$Sn$_2$ and kagome metals with CDW instabilities, and suggest a unique interplay between phonon and electron dynamics in this compound. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_05139 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Coherent phonon and unconventional carriers in the magnetic kagome metal Fe$_3$Sn$_2$ Gonçalves-Faria, M. V. Pashkin, A. Wang, Q. Lei, H. C. Winnerl, S. Tsirlin, A. A. Helm, M. Uykur, E. Strongly Correlated Electrons Materials Science Temperature- and fluence-dependent carrier dynamics of the magnetic Kagome metal Fe$_3$Sn$_2$ were studied using the ultrafast optical pump-probe technique. Two carrier relaxation processes ($τ_1$ and $τ_2$) and a laser induced coherent optical phonon were observed. By using the two-temperature model for metals, we ascribe the shorter relaxation $τ_1$ (~1 ps) to hot electrons transferring their energy to the crystal lattice via electron-phonon scattering. $τ_2$ (~25 ps), on the other hand, cannot be explained as a conventional process and is attributed to the unconventional (localized) carriers in the material. The observed coherent oscillation is assigned to be a totally symmetric A$_{1g}$ optical phonon dominated by Sn displacements out of the Kagome planes, and possesses a prominently large amplitude, on the order of 10$^{-3}$, comparable to the maximum of the reflectivity change ($Δ$R/R). This amplitude is equivalent to charge-density-wave (CDW) systems, although no signs of such an instability were hitherto reported in Fe$_3$Sn$_2$. Our results set an unexpected connection between Fe$_3$Sn$_2$ and kagome metals with CDW instabilities, and suggest a unique interplay between phonon and electron dynamics in this compound. |
| title | Coherent phonon and unconventional carriers in the magnetic kagome metal Fe$_3$Sn$_2$ |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2307.05139 |