Optical control of 4<i>f</i> orbital state in rare-earth metals.

Thielemann-Kühn, Nele; Amrhein, Tim; Bronsch, Wibke; Jana, Somnath; Pontius, Niko; Engel, Robin Y; Miedema, Piter S; Legut, Dominik et al. · Sci Adv · 2024

basic_science · Level V

Where this comes from

Abstract

A change of orbital state alters the coupling between ions and their surroundings drastically. Orbital excitations are hence key to understand and control interaction of ions. Rare-earth elements with strong magneto-crystalline anisotropy (MCA) are important ingredients for magnetic devices. Thus, control of their localized 4<i>f</i> magnetic moments and anisotropy is one major challenge in ultrafast spin physics. With time-resolved x-ray absorption and resonant inelastic scattering experiments, we show for Tb metal that 4<i>f</i>-electronic excitations out of the ground-state multiplet occur after optical pumping. These excitations are driven by inelastic 5<i>d</i>-4<i>f</i>-electron scattering, altering the 4<i>f</i>-orbital state and consequently the MCA with important implications for magnetization dynamics in 4<i>f</i>-metals and more general for the excitation of localized electronic states in correlated materials.