Dehybridization of f and d states in the heavy-fermion system YbRh2Si2
| Autor: | Sung-Kwan Mo, Patrick S. Kirchmann, Heike Pfau, D. Leuenberger, Zhi-Xun Shen, Shuolong Yang, Jonathan Sobota, Zachary Fisk, Dae-Jeong Kim |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Valence (chemistry) Lattice temperature Condensed matter physics Photoemission spectroscopy Scattering Binding energy Scale of temperature 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Excited state Heavy fermion 0103 physical sciences 010306 general physics 0210 nano-technology |
| Zdroj: | Physical Review B. 97 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | We report an optically induced reduction of the $f\text{\ensuremath{-}}d$ hybridization in the prototypical heavy-fermion compound ${\mathrm{YbRh}}_{2}{\mathrm{Si}}_{2}$. We use femtosecond time- and angle-resolved photoemission spectroscopy to monitor changes of spectral weight and binding energies of the Yb $4f$ and Rh $4d$ states before the lattice temperature increases after pumping. Overall, the $f\text{\ensuremath{-}}d$ hybridization decreases smoothly with increasing electronic temperature up to $\ensuremath{\sim}250\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ but changes slope at $\ensuremath{\sim}100\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. This temperature scale coincides with the onset of coherent Kondo scattering and with thermally populating the first excited crystal electrical field level. Extending previous photoemission studies, we observe a persistent $f\text{\ensuremath{-}}d$ hybridization up to at least $\ensuremath{\sim}250\phantom{\rule{0.28em}{0ex}}\mathrm{K}$, which is far larger than the coherence temperature defined by transport but in agreement with the temperature dependence of the noninteger Yb valence. Our data underlines the distinction of probes accessing spin and charge degrees of freedom in strongly correlated systems. |
| Databáze: | OpenAIRE |
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