# Temperature-dependent photo-response in multiferroic BiFeO$_3$ revealed by transmission measurements

## TL;DR

This study investigates how temperature affects the photo-response of BiFeO$_3$ crystals, revealing exciton-related absorption features and their coupling with lattice vibrations and magnetic phases, relevant for ultrafast photostriction.

## Contribution

It provides new insights into the temperature-dependent excitonic effects and their coupling with lattice and magnetic properties in BiFeO$_3$, advancing understanding of its photo-induced phenomena.

## Key findings

- Observation of light-induced absorption features linked to excitons
- Temperature dependence suggests coupling with lattice vibrations
- Hints of anomalies related to magnetic phase transitions

## Abstract

We studied the light-induced effects in BiFeO$_3$ single crystals as a function of temperature by means of optical spectroscopy. Here we report the observation of several light-induced absorption features, which are discussed in terms of the photostriction effect and are interpreted in terms of excitons. The temperature dependence of their energy position suggests a possible coupling between the excitons and the lattice vibrations. Moreover, there are hints for anomalies in the temperature evolution of the excitonic features, which might be related to the temperature-induced magnetic phase transitions in BiFeO$_3$. Our findings suggest a coupling between light-induced excitons and the lattice and spin degrees of freedom, which might be relevant for the observed ultrafast photostriction effect in multiferroic BiFeO$_3$.