Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 86: Correlated Electrons: Other Materials
TT 86.5: Talk
Thursday, April 3, 2014, 10:30–10:45, BEY 81
The origin of orbital and magnetic order in K2CuF4 — •Guoren Zhang1, Erik Koch2, and Eva Pavarini1 — 1Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany — 2German Research School for Simulation Sciences, 52425 Jülich, Germany
In this work, we investigate the origin of magnetic and orbital order in K2CuF4. We first construct Wannier functions from the Bloch states obtained by local-density approximation calculations with the full-potential linearized augmented plane-wave method. Then, by perturbative theory, we calculate magnetic couplings which are in good agreement with experimental results both for the ambient and high pressure structures. To investigate the origin of orbital order, we perform calculations with local-density approximation+dynamical mean-field theory method. We discuss the roles of crystal-field[1], superexchange and the charge-transfer effects[2] on the orbital ordering.
[1] K. I. Kugel and D. I. Khomskii, Zh. Eksp. Teor. Fiz. 64, 1429 (1973) [Sov. Phys. JETP 37, 725 (1973)].
[2] M.V. Mostovoy and D. I. Khomskii, Phys. Rev. Lett. 92, 167201 (2004).