Optical study of RbV$_3$Sb$_5$: Multiple density-wave gaps and phonon anomalies
| Autor: | Wenzel, M., Ortiz, B. R., Wilson, S. D., Dressel, M., Tsirlin, A. A., Uykur, E. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 105, 245123 (2022) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.105.245123 |
| Popis: | Temperature-dependent reflectivity studies on the non-magnetic kagome metal RbV$_3$Sb$_5$ in a broad energy range (50 cm$^{-1}$ $-$ 20000 cm$^{-1}$, equivalent to 6 meV $-$ 2.5 eV) down to 10 K are reported. Below $T_{\rm CDW}=102$ K, the optical spectra demonstrate a prominent spectral-weight transfer from low to higher energies as the fingerprint of the charge-density wave (CDW) formation with the opening of a partial gap. A detailed analysis reveals two energy scales of, respectively, $\sim$ 800 cm$^{-1}$ (100 meV) and 360 cm$^{-1}$ (45 meV), the latter visible below 50 K only. Additionally, two modes at, respectively, 160 cm$^{-1}$ (20 meV) and 430 cm$^{-1}$ (53 meV) can be traced both above and below $T_{\rm CDW}$. They show strong anomalies already above $T_{\rm CDW}$ with a further renormalization across the transition, suggesting the importance of the electron-phonon coupling in RbV$_3$Sb$_5$ in both normal and CDW states. While the 160 cm$^{-1}$ mode can be attributed to the E$_{1u}$ phonon, the 430 cm$^{-1}$ mode could not be reproduced in our phonon calculations. The antiresonance nature of this mode suggests a nontrivial electron-phonon coupling in RbV$_3$Sb$_5$. A distinct localization peak observed at all temperatures signals damped electron dynamics, whereas the reduced Drude spectral weight manifests moderate deviations from the band picture in RbV$_3$Sb$_5$. Comment: 14 pages, 12 figures |
| Databáze: | arXiv |
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