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HL: Fachverband Halbleiterphysik

HL 4: Complex Oxides: Bulk Properties (jointly with DS, HL, KFM, MA, O) (joint session TT/HL/MA)

HL 4.7: 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 [1]. We find that electronic correlations are important to explain the electronic structure, magnetic state, and lattice stability of RNiO₃ (R = Lu, Y, and Bi).

[1] I. Leonov et al., Phys. Rev. B 100, 161112(R) (2019).