# Dynamics of a Persistent Insulator-to-Metal Transition in Strained Manganite Films

## TL;DR

This study investigates the ultrafast, persistent insulator-to-metal transition in strained manganite films, revealing a multi-step process driven by charge order melting and phase growth, modeled by a time-dependent Ginzburg-Landau approach.

## Contribution

It demonstrates a detailed multi-step mechanism for the persistent phase transition in strained manganites, combining experimental spectroscopy with theoretical modeling.

## Key findings

- Optical excitation induces a persistent metallic phase below 100 K.
- The transition involves charge order melting followed by phase growth.
- A Ginzburg-Landau model captures the dynamics of the transition.

## Abstract

Transition metal oxides possess complex free energy surfaces with competing degrees of freedom. Photoexcitation allows shaping of such rich energy landscapes. In epitaxially strained $\mathrm{La_{0.67}Ca_{0.33}MnO_3}$, optical excitation with a sub-100 fs pulse above $2\ \mathrm{mJ/cm^2}$ leads to a persistent metallic phase below 100 K. Using single-shot optical and terahertz spectroscopy, we show that this phase transition is a multi-step process. We conclude that the phase transition is driven by partial charge order melting, followed by growth of the persistent metallic phase on longer timescales. A time-dependent Ginzburg-Landau model can describe the fast dynamics of the reflectivity, followed by longer timescale in-growth of the metallic phase.