Charge-density wave gap and Ce 4f states in CeTe2 observed by photoemission spectroscopy

Abstract

The electronic structure of an f-electron charge-density-wave (CDW) system, CeTe2, has been investigated using high-resolution angle-resolved photoemission spectroscopy (ARPES). Two gaps of similar to 100 and similar to 500 meV have been observed both along Gamma X and Gamma Y, implying the 2x2 lattice deformation in the Te(1) sheets with the CDW gap of approximate to 100 meV. By employing the fine-structure (FS) resonance, the experimental Ce 4f ARPES spectra have been measured. The FS resonance ARPES shows a typical two-peak structure with the peaks at similar to-4 and similar to-1 eV, and the weight shift in the latter peak in contrast to the traditional giant resonance. The Ce 4f states have the negligibly small intensity near E-F, reflecting the minor contribution from Ce 4f electrons to the metallic ground state of CeTe2. This study reveals that the carriers near E-F should have mainly the Te(1) 5p and Ce 5d character, but that only the Ce 5d bands cross E-F.