Photoemission spectroscopy and x-ray absorption spectroscopy study of delafossite AgTO2 (T=Fe,Co,Ni)

Abstract

Electronic structures of delafossite AgTO2 (T=Fe,Co,Ni) have been investigated by using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The T 2p XAS spectra of AgTO2 show that Fe and Co ions are in the trivalent states but that Ni ions are mainly in the divalent states, suggesting that the metallic nature of AgNiO2 arises from hole carriers due to divalent Ni ions. The valence-band PES study of AgTO2 (T=Co,Ni) reveals that T 3d states are located close to EF and that the Ni 3d band is more metalliclike than the Co 3d band.