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Electronic structure and magnetic coupling of pure and Mg-doped KCuF3

P. Ghigna;
2018-01-01
2018
ADVANCES IN CONDENSED MATTER PHYSICS
sì
WOS:000442894900001
2-s2.0-85052719506
Esperti anonimi
Inglese
Internazionale
STAMPA
2018
1
11
11
We investigated the electronic and magnetic properties of KCuF3 and KCu0.873 Mg0.125F3 crystals by means of Density Functional periodic computations at the B3LYP level of theory. We considered four possible magnetic ordering of the unpaired electrons on copper ions. Both materials are correctly predicted as being ID antiferromagnetic insulators, and the superexchange parameters in the crystallographic ab planes and along the c direction measure +10 and -600 K, respectively. Residual spin polarization is found also on fluorine atoms, in agreement with literature results. We found a complete orbital ordering at Cu sites: in the copper reference frame d(xy),d(yz),d(xz), and d(z2) orbitals contain about 2 electrons each, while the d(x)2(-y)2 orbital is only partially filled. The perturbation induced by oping of KCuF(3 )with Mg is very strong and localized on the first shell of F neighbours. Mg has a very small influence on the ordering of the 3d orbitals of copper and on the Cu-Cu magnetic superexchange parameters but reduces significantly the absolute energy differences between the antiferromagnetic ground state and the ferromagnetic phase, in agreement with the experiment. The absence of long range effects makes Mg a suitable dopant for the investigation of strongly correlated electronic systems by means of orbital dilution.
Condensed Matter Physics
http://www.hindawi.com/journals/acmp/
no
5
info:eu-repo/semantics/article
262
Cargnoni, F.; Cenedese, S.; Ghigna, P.; Trioni, M. I.; Scavini, M.
1 Contributo su Rivista::1.1 Articolo in rivista
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1.1 Articolo in rivista
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1226106
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