Dresden 2020 – wissenschaftliches Programm
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MA 3.7: Vortrag
Montag, 16. März 2020, 11:00–11:15, HSZ 201
Interplay of electronic correlations, charge disproportionation and lattice in RNiO3 nickelates with R = Lu, Y, and Bi — •Ivan Leonov — M. N. Mikheev Inst. of Metal Physics, Yekaterinburg, Russia — NUST ’MISiS’, Moscow, Russia
In recent years, increasing attention has been drawn to the understanding of the rare-earth-element nickelate perovskites RNiO3, which exhibit a sharp metal-insulator transition (MIT). The MIT is accompanied by a structural phase transformation, complicated by the appearance of unusual charge order and non-collinear magnetic phases in the Mott insulating regime. Here, I will focus on this particular problem and will discuss an application of the DFT+DMFT method to explore the electronic structure, magnetic and lattice properties of a series of RNiO3 nickelates with R = Lu, Y, and Bi. I will discuss our results for the pressure-induced Mott MIT in RNiO3, which is found to be accompanied by a structural transformation. While the rare-earth and Bi RNiO3 are closely related in their electronic state and crystal structure, these materials exhibit sufficiently different electronic properties. Our results for BiNiO3 suggest the important role of the Bi 4s charge ordering (charge difference of ∼0.52 electrons), with a charge transfer between the Bi 4s and O 2p states and a stable Ni2+ configuration, for understanding of the MIT in BiNiO3 . We find that electronic correlations are important to explain the electronic structure, magnetic state, and lattice stability of RNiO3 (R = Lu, Y, and Bi).
 I. Leonov et al., Phys. Rev. B 100, 161112(R) (2019).