Coherent energy scale revealed by ultrafast dynamics of UX$_{3}$ (X=Al, Sn, Ga) single crystals
| Autor: | Nair, Saritha K., Zhu, J. -X., Sarrao, J. L., Taylor, A. J., Chia, Elbert E. M. |
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| Rok vydání: | 2012 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.86.115103 |
| Popis: | Temperature dependence of relaxation dynamics of UX$_{3}$ (X = Al, Ga, Sn) compounds is studied using time resolved pump-probe technique in the reflectance geometry. UGa$_{3}$ is an itinerant antiferromagnet, while UAl$_{3}$ and USn$_{3}$ are spin fluctuation systems. For UGa$_{3}$, our data are consistent with the formation of a spin density wave SDW gap as evidenced from the quasidivergence of the relaxation time $\tau$ near the N\'{e}el temperature $T_{N}$. For UAl$_{3}$ and USn$_{3}$, the relaxation dynamics shows a change from single exponential to two exponential behavior below a particular temperature, suggestive of coherence formation of the 5\textit{f} electrons with the conduction band electrons. This particular temperature can be attributed to the spin fluctuation temperature $T_{sf}$, a measure of the strength of Kondo coherence. Our $T_{sf}$ is consistent with other data such as resistivity and susceptibility measurements. The temperature dependence of the relaxation amplitude and time of UAl$_{3}$ and USn$_{3}$ were also fitted by the Rothwarf-Taylor model. Our results show ultrafast optical spectroscopy is sensitive to c-\textit{f} Kondo hybridization in the \textit{f}-electron systems. Comment: 6 pages, 5 figures |
| Databáze: | arXiv |
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