Evidence of photo-induced dynamic competition of metallic and insulating phase in a layered manganite

TL;DR

This study demonstrates that ultrafast optical excitation can manipulate the competition between metallic and insulating phases in layered manganite, revealing dynamic phase control at the reentrant phase boundary.

Contribution

It provides experimental evidence of photo-induced control over phase competition in layered manganite using time-resolved measurements of Jahn-Teller reflections.

Findings

Laser excitation modulates charge and orbital order.

Reversal of Jahn-Teller reflection sign occurs over time.

Phase competition can be dynamically controlled by light.

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, LaSr2Mn2O7, 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.