The interplay of local electron correlations and ultrafast spin dynamics in fcc Ni
Tobias Lojewski, Mohamed F. Elhanoty, Loïc Le Guyader, Oscar Grånäs, Naman Agarwal, Christine Boeglin, Robert Carley, A. Castoldi, Christian Dávid, Carsten Deiter, Florian Döring, RobinY Engel, Florian Erdinger, Hans Fangohr, C. Fiorini, Peter Fischer, Natalia Gerasimova, Rafael Gort, Frank M. F. deGroot, K. Hansen, Steffen Hauf, David Hickin, Manuel Izquierdo, Benjamin E. Van Kuiken, Y. O. Kvashnin, Charles‐Henri Lambert, D. Lomidze, Stefano Maffessanti, Laurent Mercadier, Giuseppe Mercurio, Piter S. Miedema, Katharina Ollefs, Matthias Pace, M. Porro, S.J. Rezvani, Benedikt Rösner, Nico Rothenbach, A. Samartsev, Andreas Scherz, J. Schlappa, Christian Stamm, Martin Teichmann, Patrik Thunström, M. Turcato, Alexander Yaroslavtsev, Jun Zhu, Martin Beye, Heiko Wende, U. Bovensiepen, Olle Eriksson, Andrea Eschenlohr
Abstract
The complex electronic structure of metallic ferromagnets is determined by a balance between exchange interaction, electron hopping leading to band formation, and local Coulomb repulsion. By combining high energy and temporal resolution in femtosecond time-resolved X-ray absorption spectroscopy with ab initio time-dependent density functional theory we analyze the electronic structure in fcc Ni on the time scale of these interactions in a pump-probe experiment. We distinguish transient broadening and energy shifts in the absorption spectra, which we demonstrate to be captured by electron repopulation respectively correlation-induced modifications of the electronic structure, requiring to take the local Coulomb interaction into account.