Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 54: Focus Session: Frontiers of electronic structure theory IV (O, jointly with HL, TT)
HL 54.9: Talk
Wednesday, March 13, 2013, 12:45–13:00, H36
Electronic Structure and Magnetic interactions in 5d Ir oxide compounds — •Vamshi Mohan Katukuri1, Viktor Yushankhai2, Radu Coldea3, Liviu Hozoi1, and Jeroen van den Brink1 — 1Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20 01069 Dresden, Germany — 2Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Russia — 3Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
We investigate the correlated d-level electronic structure and magnetic interactions of 5d Ir oxide compounds by fully ab initio quantum-chemical many-body calculations on finite embedded clusters. The wave-function quantum-chemical methods provide a promising alternative to density-functional-based approaches to the electronic structure of solids. The computed d-d excitations in square-lattice, honeycomb, pyrochlore, and chain-like iridates compare well with recent RIXS (resonant inelastic x-ray scattering) data. We also perform a detailed analysis of the relativistic spin-orbit wave functions and compute observables such as the ⟨ L·S ⟩ ground-state expectation value of the spin-orbit operator. The latter is in principle accessible from x-ray absorption and provides information on the role of t2g– eg couplings in the ground-state wave function and on the strength of non-cubic fields that lift the degeneracy of the t2g levels. As concerns to the magnetic structure, we find, in honeycomb lattice structures, A2IrO3, the magnetic interactions strongly deviate from the proposed Kitaev-Heisenberg model, due to low-symmetry crystal fields.