Large Photoelasticity in Topological Antiferromagnet Mn$_3$Sn Studied by Coherent Acoustic Phonon

TL;DR

This study reveals exceptionally large photoelastic effects in Mn$_3$Sn thin films, demonstrating significant optical responses to ultrafast strain with potential applications in opto-spintronic and optoacoustic devices.

Contribution

It provides a quantitative analysis of ultrafast strain-induced optical responses in topological antiferromagnet Mn$_3$Sn, highlighting its unusually large photoelastic coefficient.

Findings

Large amplitude coherent acoustic phonons with over 1% differential transmission.

Photoelastic coefficient in Mn$_3$Sn is several times larger than in typical materials.

Potential for opto-spintronic and optoacoustic applications at telecom wavelengths.

Abstract

We investigate the relation of electronic and optical properties to ultrafast strain in topological antiferromagnet Mn$_3$Sn thin films using near-infrared femtosecond laser pulses. Coherent acoustic phonon oscillations are generated and clearly identified with a remarkably large amplitude exceeding 1% in differential transmission. Quantitative analysis reveals that near-infrared photoelastic coefficient in Mn$_3$Sn is several times larger than that in typical materials. These results establish a quantitative approach for understanding the large optical responses to ultrafast strain in the topological kagome antiferromagnet, suggesting potential opto-spintronic and optoacoustic applications even at telecommunications wavelength.