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arXiv · 1909.00199

Element specificity of transient extreme ultra-violet magnetic dichroism

J. K. Dewhurst·F. Willems·P. Elliott·Q. Z. Li·C. von Korff Schmising·C. Strueber·D. W. Engel·S. Eisebitt·S. Sharma
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Abstract

In this work we combine theory and experiment to study transient magnetic circular dichroism (tr-MCD) in the extreme ultraviolet spectral range (XUV) in bulk Co and CoPt. We use the \emph{ab-initio} method of real-time time-dependent density functional theory (RT-TDDFT) to simulate the magnetization dynamics in the presence of ultrafast laser pulses. From this we demonstrate how tr-MCD may be calculated using an approximation to the excited-state linear-response. We apply this approximation to Co and CoPt and show computationally that element-specific dynamics of the local spin moments can be extracted from the tr-MCD in XUV energy range, as is commonly assumed. We then compare our theoretical prediction for the tr-MCD for CoPt with experimental measurement and find excellent agreement at many different frequencies including the $M_{2 3}$-edge of Co and $N_{6 7}$- and $O_{2 3}$- edges of Pt.

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J. K. Dewhurst, F. Willems, P. Elliott, Q. Z. Li, C. von Korff Schmising, C. Strueber, D. W. Engel, S. Eisebitt, S. Sharma. 2019-08-31. Element specificity of transient extreme ultra-violet magnetic dichroism. https://doi.org/10.1103/physrevlett.124.077203

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