Abstract
Electronic structures of delafossite oxides and the frustrated Jahn-Teller (JT) system have been investigated by employing soft x-ray absorption spectroscopy and photoemission spectroscopy (PES). It is found that Ni ions are in the mixed-valent states and that the low-spin (LS) component increases from to and , in agreement with the presence of the JT transition in and the absence of the JT transition in and . In , the component increases with , while Co ions are in the LS states for all , which is consistent with the metallic nature for low values of . A good agreement is found between the measured PES spectra and the calculated local spin density approximation (LSDA) electronic structures of and , but the pseudogap feature in PES of is not described by the LSDA.
- Received 16 September 2007
DOI:https://doi.org/10.1103/PhysRevB.76.195122
©2007 American Physical Society