Magneto-Optical Functions at the 3p Resonances of Fe, Co, and Ni: Ab initio Description and Experiment

Abstract

We present theoretical and experimental data on the magneto-optical contributions to the complex refractive index in the extreme ultraviolet (XUV) range covering the 3p resonances of Fe, Co, and Ni. Comparing the spectra from density functional theory with magnetic circular dichroism measurements we find that many body corrections and local field effects are of crucial importance for accurate description of the spectra. Our results are relevant for the application of static XUV spectroscopy for multi element magnetic systems as well as for the investigation of ultrafast magnetization dynamics. arXiv:1812.06703v1 [cond-mat.mtrl-sci]

Element Specificity of Transient Extreme Ultraviolet Magnetic Dichroism

“…This extends the good agreement between experiment and theory found in Ref. [18] for simple ferromagnets to the case of more complex materials. Furthermore, we can numerically decompose the total MCD signal into contributions for the Co and Pt individually.…”

“…At this point it is important to note the difference between the results for bulk Co in the present case and in the previous work in Ref. 18-there are three differences: (i) in the present work an average width of 1 eV for 3p 1/2 and 3p 3/2 states is considered, while in the previous work a state dependent width was used. The net result of this is that the intensity of the post M 23 -edge peak is large, (ii) in the present work states up to 90 eV above the Fermi level are used, while in the previous work states up to 300 eV above the Fermi level were used.…”

“…It was also shown in Ref. [18] that many-body correction to the KS band structure are important. In the present work we have included these corrections by first calculating a fully spin-polarized GW spectral function to determine the correct position of the Co 3p, Pt 4f and 5p states and then red shifting the KS states to these correct energies.…”

“…This in turn allows for inclusion of the microscopic components known as the local field effects (LFE). These LFE are crucial for accurate description of the response function [18]. In the present work these LFE are included and we found that we needed a matrix of 70 × 70 for convergence.…”

“…This approach has been very successful for calculating the static magneto-optical response function for Fe, Co and Ni [18].…”