Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Computational Magnetism 2

MA 15.1: Talk

Tuesday, September 6, 2022, 09:30–09:45, H48

An ab initio study of temperature effects on the optical and magneto-optical properties of ferromagnetic BCC Fe — •Kisung Kang, David G. Cahill, and André Schleife — Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

This work investigates the temperature-dependent optical properties of ferromagnetic BCC Fe in terms of electron, lattice, and magnetic temperatures. With the supercell approach, lattice and magnetic temperature is portrayed by the perturbed atomic and magnetic structures at finite temperature. In imaginary optical conductivity spectra at finite temperature, a large signal at low energy range is induced by phonon and magnon-assisted intraband transitions. We identify that this surging signal originates from the change of the dipole transition matrix elements. Magnetic temperature provokes a unique spectral change which is a redshift of the peak near 2.8 eV in the imaginary optical conductivity spectrum. From band unfolding analysis, it turns out that thermal demagnetization induces the reduction of exchange splitting in the electronic band structure, leading to the electron excitation with a smaller energy transition and explaining the peak redshifting. **Illinois MRSEC NSF DMR-1720633 Kisung Kang’s present address: The NOMAD laboratory, Fritz-Haber-Institut der Max-Placnk-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany