Separating Exchange Splitting from Spin Mixing in Gadolinium by Femtosecond Laser Excitation
| Autor: | Cornelius Gahl, Jürgen Kirschner, Martin Weinelt, Marc Christ, Beatrice Andres, Marko Wietstruk |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 115 |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.115.207404 |
| Popis: | Employing spin-, time-, and energy-resolved photoemission spectroscopy, we present the first study on the spin polarization of a single electronic state after ultrafast optical excitation. Our investigation concentrates on the majority-spin component of the $d$-band-derived Gd(0001) surface state ${d}_{{z}^{2}}^{\ensuremath{\uparrow}}$. While its binding energy shows a rapid Stoner-like shift by 90 meV with an exponential time constant of ${\ensuremath{\tau}}_{E}=0.6\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{ }\mathrm{ps}$, the ${d}_{{z}^{2}}^{\ensuremath{\uparrow}}$ spin polarization remains nearly constant within the first picoseconds and decays with ${\ensuremath{\tau}}_{S}=15\ifmmode\pm\else\textpm\fi{}8\text{ }\text{ }\mathrm{ps}$. This behavior is in clear contrast to the equilibrium phase transition, where the spin polarization vanishes at the Curie temperature. |
| Databáze: | OpenAIRE |
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