Nature of hole doping in Nd2NiO4 and La2NiO4: Comparison with La2CuO4

Zhengquan Tan, S. M. Heald, S. W. Cheong, A. S. Cooper, A. R. Moodenbaugh

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

To elucidate the hole doping mechanism, we have systematically studied the Ni and Cu K-edge x-ray-absorption spectra in doped Nd2NiO4, La2NiO4, and La2CuO4. We find a significant difference in the character of the doped hole between the nickelates and cuprate. We observe that both strontium substitution and introduction of excess oxygen lead to a shift of the Ni absorption edge to higher energies, by nearly 3 eV in NaSrNiO4. This result demonstrates that the doped holes, in addition to the O 2p character, have a substantial amount of Ni 3d character (30-40 %). The intensity of the 1s-3d transition increases upon doping, consistent with increasing number of d holes. In contrast, the Cu absorption edge in the doped cuprate is shifted by much smaller amounts, indicative of a lower amount of Cu 3d character for the doped hole. The strongly mixed Ni 3d and O 2p character of the doped hole distinguishes the electronic structure of the nickelate from that of the cuprate.

Original languageEnglish (US)
Pages (from-to)12365-12368
Number of pages4
JournalPhysical Review B
Volume47
Issue number18
DOIs
StatePublished - Jan 1 1993

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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