Doping dependence and electron–boson coupling in the ultrafast relaxation of hot electron populations in Ba(Fe1–xCox)2As2
| Autor: | I Avigo, S Thirupathaiah, M Ligges, T Wolf, J Fink, U Bovensiepen |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | New Journal of Physics, Vol 18, Iss 9, p 093028 (2016) |
| Druh dokumentu: | article |
| ISSN: | 1367-2630 59916230 |
| DOI: | 10.1088/1367-2630/18/9/093028 |
| Popis: | Using femtosecond time- and angle-resolved photoemission spectroscopy we investigate the effect of electron doping on the electron dynamics in $\mathrm{Ba}{({\mathrm{Fe}}_{1-x}{\mathrm{Co}}_{x})}_{2}{\mathrm{As}}_{2}$ in a range of $0\leqslant x\lt 0.15$ at temperatures slightly above the Néel temperature. By analyzing the time-dependent photoemission intensity of the pump laser excited population as a function of energy, we found that the relaxation times at $0\lt E-{E}_{{\rm{F}}}\lt 0.2\,\mathrm{eV}$ are doping dependent and about 100 fs shorter at optimal doping than for overdoped and parent compounds. Analysis of the relaxation rates also reveals the presence of a pump fluence dependent step in the relaxation time at $E-{E}_{{\rm{F}}}=200\,\mathrm{meV}$ which we explain by coupling of the excited electronic system to a boson of this energy. We compare our results with static ARPES and transport measurements and find disagreement and agreement concerning the doping-dependence, respectively. We discuss the effect of the electron–boson coupling on the energy-dependent relaxation and assign the origin of the boson to a magnetic excitation. |
| Databáze: | Directory of Open Access Journals |
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