1209.5294 (X. Liu et al.)

Testing the validity of the strong spin-orbit-coupling limit for
octahedrally coordinated iridates in a model system Sr$_3$CuIrO$_6$    [PDF]

X. Liu, Vamshi M. Katukuri, L. Hozoi, Wei-Guo Yin, M. P. M. Dean, M. H. Upton, Jungho Kim, D. Casa, A. Said, T. Gog, T. F. Qi, G. Cao, A. M. Tsvelik, Jeroen van den Brink, J. P. Hill

The electronic structure of Sr$_3$CuIrO$_6$, a model system for the 5d Ir ion in an octahedral environment, is studied through a combination of resonant inelastic x-ray scattering (RIXS) and theoretical calculations. RIXS spectra at the Ir L$_3$-edge reveal an Ir $t_{2g}$ manifold that is split into three levels, in contrast to the expectations of the strong spin-orbit-coupling limit. Effective Hamiltonian and $ab inito$ quantum chemistry calculations find a strikingly large non-cubic crystal field splitting comparable to the spin-orbit coupling, which results in a strong mixing of the $j_{\mathsf{eff}}=1/2$ and $j_{\mathsf{eff}}=3/2$ states and modifies the isotropic wavefunctions on which many theoretical models are based.

View original: http://arxiv.org/abs/1209.5294