Resonant photoemission spectroscopy of the ferromagnetic Kondo system CeAgSb2. (7th July 2021)

• Record Type: Journal Article
• Authors: Chuang, C W; Chiogo, B Tegomo; Malterre, D; Chuang, P-Y; Cheng, C-M; Pi, T-W; Chang, F-H; Lin, H-J; Chen, C-T; Kuo, C-N; Lue, C-S; Chainani, A
• Is Part Of: Electronic structure. Volume 3:Number 3(2021)
• Publication Date: 2021-07-07
• Subjects: Kondo material -- resonant photoemission spectroscopy -- x-ray absorption spectroscopy; Electronic structure -- Periodicals; 530.411
• DOI: 10.1088/2516-1075/ac0c25
• Languages: English
• ISSNs: 2516-1075

Abstract

Abstract: We study the electronic structure of single crystal CeAgSb2, a low T c ferromagnetic Kondo system, using synchrotron radiation photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). We have carried out Ce 5 s, Ce 5 p, Sb 4 d core level PES as well as Ce 4 d –4 f resonant PES of the valence band states of CeAgSb2 . We also report the resonant PES behavior of Ce 5 s and 5 p core-levels and the simultaneous intensity suppression of Sb 4 d core-level and Ag 4 d valence band states across the Ce 4 d –4 f threshold. The Ce 4 d –4 f resonant valence band spectra show typical f 0 and f 1 features associated with Kondo behavior. The constant initial state spectra of the f 0 and f 1 features show maxima at different incident photon energies, arising from different relative contributions of surface and bulk character Ce 4 f partial density of states. XAS across the Ce 3 d –4 f M -edge also shows the corresponding final state f 1 and f 2 features. The weak temperature dependence of the XAS spectra between T = 25 K and 300 K could be simulated using a full multiplet calculation combined with a simplified single-impurity Anderson model approach. The calculations confirm the Kondo screening and allows quantification of the bulk Ce 4 f electron count in CeAgSb2 . The Ce 5 s states show an exchange splitting which reflects the local magnetic moment of Ce 4 f states. The overall results characterize the bulk and surface sensitive Ce 4 f states, and indicate the role of Kondo effect in forming the moderately enhanced heavy-fermion carriers in CeAgSb2 .