Studies on the electronic structure of Ag2NiO2, an intercalated delafossite containing subvalent silver

Structural and electronic properties of Ag2NiO2 and AgNiO2 were investigated and compared. Single crystal X-ray diffraction experiments on Ag2NiO2 at 100 K provide evidence for a ferrodistortive phase below 260 K. Ni K-edge and Ag LIII-edge XANES spectra, both measured and simulated, as well as core level and valence band photoelectron spectra are analysed. They agree well with the results of bandstructure calculations, where pure DFT and mixed Hartree–Fock/DFT (hybrid) functionals were applied and spin-polarisation was considered. The electronic structure of the [NiO2]− layers with Ni3+ in a low spin state, forming a spin-1/2 triangular lattice, is very similar in both compounds. A ferrimagnetic alignment of the spins within the [NiO2]− layers and their antiferromagnetic coupling via the intermediate silver layers is suggested.

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