# Evidence of structural evolution in Sr2RhO4 studied by time-resolved optical reflectivity spectroscopy

## TL;DR

This study uses ultrafast optical spectroscopy to reveal temperature-dependent electronic and structural changes in Sr2RhO4, showing a phase transition around 160 K that affects carrier dynamics and phonon behavior.

## Contribution

It provides direct evidence of structural evolution in Sr2RhO4 through time-resolved reflectivity and phonon phase shifts, linking structural changes to electronic dynamics.

## Key findings

- Electronic dynamics slow down below 160 K.
- Coherent phonon phase shifts across the transition.
- Structural evolution influences carrier and phonon responses.

## Abstract

We investigate ultrafast dynamics from photoinduced reflectivity of Sr2RhO4 by using femtosecond near-infrared pulses. We observe a clear temperature-dependent anomaly in its electronic dynamics which slows down below 160 K. In addition, coherent oscillations of the A1g symmetric 5.3-THz phonon exhibit a 90-degree shift in its initial phase across TS, indicating a structural change in octahedral rotation distortions. We propose that octahedral structure in Sr2RhO4 evolves at around TS, and it can influence on the non-equilibrium dynamics of photoinduced carriers as well as real-time phonon responses.