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arXiv · 1611.10009

Cooperative Phenomena in Spin Crossover Systems

Alexander I. Nesterov·Yuri S. Orlov·Sergey G. Ovchinnikov·Sergey V. Nikolaev
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Abstract

Within the framework of a realistic multi-band p-d-model, we derived an effective Hamiltonian to describe the exchange interaction effects near the spin crossover in magnetic Mott-Hubbard insulators under pressure. It is shown that single-ion mechanism of spin crossover under change of the crystal field does not lead to a thermodynamic phase transition, however, at T = 0 a quantum phase transition appears. It has been found that the cooperativity leads to a modification of the quantum phase transition to a first-order phase transition and the appearance of metastable states of the system. The pressure - temperature phase diagram has been obtained to describe the magnetization and high-spin population near the spin crossover of the Motts dielectrics with d6-ions.

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Alexander I. Nesterov, Yuri S. Orlov, Sergey G. Ovchinnikov, Sergey V. Nikolaev. 2017-03-15. Cooperative Phenomena in Spin Crossover Systems. https://doi.org/10.1103/physrevb.96.134103

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