Optical control of 4f orbital state in rare-earth metals | Science Advances
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
f
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
f
-electronic excitations out of the ground-state multiplet occur after optical pumping. These excitations are driven by inelastic 5
d
-4
f
-electron scattering, altering the 4
f
-orbital state and consequently the MCA with important implications for magnetization dynamics in 4
f
-metals and more general for the excitation of localized electronic states in correlated materials.