title: Evidence of photo-induced dynamic competition of metallic and insulating phase in a layered manganite.
abstract: We show evidence that the competition between the antiferromagetic metallic phase and the charge- and orbital-ordered insulating phase at the reentrant phase boundary of a layered manganite, La0.99Sr2.01Mn2O7, can be manipulated using ultrafast optical excitation. The time-dependent evolution of the Jahn-Teller superlattice reflection, which indicates the formation of the charge and orbital order, was measured at different laser fluences. The laser-induced enhancement and reduction the Jahn-Teller reflection intensity shows a reversal of sign between earlier (~10 ns) and later (~150 ns) time delays during the relaxation after photo excitation. This effect is consistent with a scenario whereby the laser excitation modulates the local competition between the metallic and the insulating phases.
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Li
authors.forename: Donald A
authors.initials: DA
authors.lastname: Walko
authors.forename: Qing'an
authors.initials: Q
authors.lastname: Li
authors.forename: Yaohua
authors.initials: Y
authors.lastname: Liu
authors.forename: Stephan
authors.initials: S
authors.lastname: Rosenkranz
authors.forename: Hong
authors.initials: H
authors.lastname: Zheng
authors.forename: J F
authors.initials: JF
authors.lastname: Mitchell