Fermi surface reconstruction in CeTe2 induced by charge density waves investigated via angle resolved photoemission

Abstract

Electronic structures of a charge-density wave (CDW) system CeTe2-xSbx (x = 0, 0.05) have been investigated by employing angle-resolved photoemission spectroscopy (ARPES) and the first-principles electronic and phonon band-structure methods. The observed Fermi surface (FS) agrees very well with the calculated FS for the undistorted CeTe2 both in shapes and sizes. The metallic states crossing the Fermi level (E-F) are observed in ARPES even in the CDW state. The carriers near E-F have mainly the Te(1) 5p character, with a negligible contribution from Ce 4f states. The supercell (shadow) bands and the corresponding very weak FSs are found to arise from band folding due to the interaction of Te(1) layers with Ce-Te(2) layers. We found that the CDW modulation vector is along Gamma-X (Q(CDW) approximate to X), which is not coincident with the most prominent FS nesting vector.