From NdNiO2 to a Mott Multiferroic BiNiO2.

Motivated by the recently discovered superconductivity in Sr-doped nickelate oxides NdNiO₂ reduced from NdNiO₃ in experiments, we predict a Mott multiferroic BiNiO₂ that may be obtained from BiNiO₃. There is a ferroelectric structural transition for BiNiO₂ from the nonpolar phase to the polar phase with the P4mm space group, which is driven by the lone pair on Bi. The lowest energy ground-state for polar BiNiO₂ is a Hubbard Mott insulator with the G-type antiferromagnetic spin configurations. The replacement of Nd by Bi serves as a connecting link between a parent compound of high-temperature superconductor and a Mott multiferroic. [ABSTRACT FROM AUTHOR]