2019/06/18 by Peng Li, Zhongzheng Wu, Fan Wu +14
Materials Science · Physics and Astronomy · #Angle-resolved photoemission spectroscopy #Anisotropy #Condensed matter physics #Electron #Electronic structure #Fermi level #Fermi liquid theory #Fermi surface #Iron-based superconductors research #Mixing (physics) #Photoemission spectroscopy #Physics #Quantum mechanics #Rare-earth and actinide compounds #Spectral line #Superconductivity in MgB2 and Alloys #Valence (chemistry) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.100.155110
published as Phys. Rev. B 100, 155110 (2019) · 3 figures
arxiv created 2019/06/18 · openalex created_date 2019/06/27 · openalex publication_date 2019/10/07 · arxiv updated 2019/10/16 · openalex updated_date 2026/08/06
Using angle-resolved photoemission spectroscopy (ARPES) and resonant ARPES, we report evidence of strong anisotropic conduction-f electron mixing (c\text\ensuremath-f mixing) in CeBi by observing a largely expanded Ce 5d pocket at low temperature, with no change in the Bi 6p bands. The anisotropic Fermi surface (FS) expansion is accompanied by a pronounced spectral weight transfer from the local 4f0 peak of Ce (corresponding to Ce3+) to the itinerant conduction bands near the Fermi level. Careful analysis suggests that the observed large FS change (with a volume expansion of the electron pocket up to 40%) can most naturally be explained by a small valence change (\ensuremath∼1%) of Ce, which coexists with a very weak Kondo screening. Our work therefore provides evidence for a FS change driven by real charge fluctuations deep in the Kondo limit, which is highly dependent on the orbital character and momentum and is made possible by the low carrier density.