Coupling of optical phonons with Kondo effect and magnetic orders in antiferromagnetic Kondo lattice CeAuSb$_2$

TL;DR

This study uses ultrafast optical spectroscopy to explore the hybridization gap, phonon coupling, and potential photoinduced phase transitions in the antiferromagnetic Kondo lattice CeAuSb$_2$, revealing insights into heavy fermion behavior.

Contribution

It provides new insights into hybridization dynamics and magnetic order coupling in CeAuSb$_2$ using ultrafast spectroscopy.

Findings

Detection of a narrow hybridization gap below 100 K

Coupling of phonons with Kondo and magnetic orders causing frequency anomalies

Evidence of a possible photoinduced nonthermal phase transition

Abstract

Ultrafast optical spectroscopy was used to investigate the ultrafast quasiparticle dynamics of antiferromagnetic Kondo lattice CeAuSb$_2$ as a function of temperature and fluence. Our results reveal (i) the opening of a narrow hybridization gap ($\Delta$ $\sim$ 4.5 meV) near the Fermi level below the coherence temperature $T^*$ $\approx$ 100 K, (ii) the coupling of coherent phonon modes with Kondo effect and magnetic orders, leading to the frequencies anomaly at the characteristic temperatures, and (iii) a possible photoinduced nonthermal phase transition. Our observations thus shed light on the hybridization dynamics and magnetic orders in heavy fermion systems.