Doping evolution of the electronic and magnetic structure in RENiO₃

Rare earth nickelates (RENiO₃) exhibit metal-insulator transitions accompanied by the appearance of charge and spin order, at times concurrently. The understanding of the evolving ground state in these materials is hindered by the existence of multiple competing orders which are further coupled to various kinds of local perturbations (strain, defects, disorder). Recently, control of carrier doping by means of oxygen stoichiometry has been achieved in RENiO₃, presenting an opportunity to study the broader electronic phase diagram of these systems. In this talk, I will present our recent soft X-ray absorption spectroscopy and imaging, resonant X-ray scattering, and extended multiplet ligand field theory modeling results on both pristine and electron doped RENiO₃. We identified the redistribution of the doped carriers in the correlated electronic ground state. Moreover, the magnetic order is robust to substantial levels of carrier doping until it collapses at a doping threshold. Our results reveal the doping dependent evolution of the electronic structure and magnetic phase diagram in RENiO₃.