Anisotropic Spin Models of Iridium Oxides: Justification by a Cluster Quantum-Chemical Approach

For various crystal structures of magnetic iridium oxides, a cluster quantum-chemical method has been developed for quantitative justification of effective spin models, including the Heisenberg compass model on a square lattice and the Kitaev model on a hexagonal lattice, previously proposed on a phenomenological basis and currently being intensively discussed.