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

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 ($\hat{I}”$ $\sim$ 4.5 meV) near the Fermi level below the coherence temperature $T^{\ast }$ $\approx$ 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.

6 pages with 4 figures