Interplay between lattice, orbital, and magnetic degrees of freedom in the chain-polymer Cu(II) breathing crystals
Authors:
- S. V. StreltsovSSS. V. Streltsov
- M. V. PetrovaMPM. V. Petrova
- V. A. MorozovVMV. A. Morozov
- G. V. RomanenkoGRG. V. Romanenko
- V. I. AnisimovVAV. I. Anisimov
- N. N. LukzenNLN. N. Lukzen
Preprint
Abstract
The chain-polymer Cu(II) "breathing crystals" C$_{21}$H$_{19}$CuF$_{12}$N$_4$O$_6$ were studied using the X-ray diffraction and ab initio band structure calculations. We show that the crystal structure modification at T=146 K, associated with the spin crossover transition, induces dramatic changes in the occupation of the Cu $e_g$ sub-shell in half of the Cu sites. This in turn results in the switch of the magnetic interaction sign in accordance with the Goodenough-Kanamori-Andersen theory of the coupling between the orbital and spin degrees of freedom.