Unraveling the Hybridization Process in CeAgSb2 Kondo Lattice

Abstract

We present a comprehensive investigation utilizing ultrafast optical pump-probe spectroscopy to elucidate the intricate quasiparticle dynamics in the CeAgSb₂ single crystal. Through our experimental endeavors, a nuanced two-phase evolution in the hybridization phenomena linking localized f moments and conduction electrons has been unveiled. This intricate process is manifest in two distinct manifestations: firstly, the discernible manifestation of hybridization fluctuations spanning the temperature range of approximately 150 K (denoted as T^†) down to approximately 65 K (referred to as T^*); secondly, the notable emergence of a collective hybridization phenomenon below the critical temperature, T^*, as indicated by the onset of an indirect gap in the electronic structure. These discerning observations provide invaluable insights into the interplay of electronic configurations as a function of temperature in CeAgSb₂, shedding light on its unique properties and behaviors.