title: Ultrafast momentum-dependent response of electrons in antiferromagnetic EuFe2As2 driven by optical excitation.
abstract: Employing the momentum sensitivity of time- and angle-resolved photoemission spectroscopy we demonstrate the analysis of ultrafast single- and many-particle dynamics in antiferromagnetic EuFe(2)As(2). Their separation is based on a temperature-dependent difference of photoexcited hole and electron relaxation times probing the single-particle band and the spin density wave gap, respectively. Reformation of the magnetic order occurs at 800 fs, which is 4 times slower compared to electron-phonon equilibration due to a smaller spin-dependent relaxation phase space.
authors.affiliation: Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Rettig
authors.forename: R
authors.initials: R
authors.lastname: Cortés
authors.forename: S
authors.initials: S
authors.lastname: Thirupathaiah
authors.forename: P
authors.initials: P
authors.lastname: Gegenwart
authors.forename: H S
authors.initials: HS
authors.lastname: Jeevan
authors.forename: M
authors.initials: M
authors.lastname: Wolf
authors.forename: J
authors.initials: J
authors.lastname: Fink
authors.forename: U
authors.initials: U
authors.lastname: Bovensiepen