Electronic structure and the metal-insulator transition in LnNiO3(Ln=La, Pr, Nd, Sm and Ho): bandstructure results

We report detailed band structure results on the series LnNiO3 with Ln=La, Pr, Nd, Sm and Ho. LaNiO3 is shown to be a pd metal, expected to be close to localization due to correlation effects; the other four compounds are suggested to be covalent insulators. There is a systematic reduction in the bandwidths with increasing atomic number of the rare-earth ion. Using a tight-binding analysis of the ab initio results, the reduction in the bandwidth is related to the changes in the intercluster hopping interaction strengths arising from the structural changes driven by the lanthanide contraction across the series.