The interplay of local electron correlations and ultrafast spin dynamics in fcc Ni

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. The interplay between the respective terms of the Hamiltonian is of fundamental interest, since it produces most, if not all, of the exotic phenomena observed in the solid state. 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 caused by electron repopulation and correlation-induced modifications of the electronic structure, respectively. Importantly, the theoretical description of this experimental result hence requires to take the local Coulomb interaction into account, revealing a temporal interplay between band formation, exchange interaction, and Coulomb repulsion.

References in corpus (8)

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Cited by in corpus (9)

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• Electron Dynamics at High-Energy Densities in Nickel from Non-linear Resonant X-ray Absorption Spectra
• A Rate Model of Electron Populations for Non-linear High-Fluence X-ray Absorption Near-Edge Spectra
• Ultrafast demagnetization in bulk nickel induced by X-ray photons tuned to Ni $M_3$ and $L_3$ absorption edges
• Table-top soft x-ray source for XAS experiments with photon energies up to 350 eV
• Femtosecond spin-state switching dynamics of spin-crossover molecules condensed in thin films
• Nonequilibrium DMFT approach to time-resolved Raman spectroscopy
• Femtosecond charge and spin dynamics in CoPt alloys