Band structure and cluster model calculations of LaNiO3 compared to photoemission, O 1s X-ray absorption, and optical absorption spectra

We studied the electronic structure of LaNiO3 using band structure and cluster model calculations. This compound is a paramagnetic metal with a R3c rhombohedral structure. The band structure was calculated using the generalized gradient approximation (GGA). The cluster model was solved using the configuration interactions (CI) many-body method. We present results for the density of states (DOS), the spectral weight, and the dielectric function e 2 . The calculations are compared to previous photoemission (PES), O 1s X-ray absorption (XAS), as well as optical absorption spectra. Both band structure and cluster model results are in good agreement with the experimental data. We point out that this concordance is very rare and far from trivial; we argue that this may be due to the unusual characteristics of the ground state of LaNiO3.