{\it Ab initio} analyses of A2IrO4 (A=Sr, Ba) are presented. Effective Hubbard-type models for Ir 5dt2g manifolds downfolded from the global band structure are solved based on the dynamical mean-field theory. The results for A=Sr and Ba correctly reproduce paramagnetic metals undergoing continuous transitions to insulators below the N\'eel temperature TN. These compounds are classified not into Mott insulators but into Slater insulators. However, the insulating gap opens by a synergy of the Neel order and significant band renormalization, which is also manifested by a 2D bad metallic behavior in the paramagnetic phase near the quantum criticality.
@article{arxiv.1107.0835,
title = {{\it Ab initio} Studies on the Interplay between Spin-Orbit Interaction and Coulomb Correlation in Sr$_2$IrO$_4$ and Ba$_2$IrO$_4$},
author = {R. Arita and J. Kuneš and A. V. Kozhevnikov and A. G. Eguiluz and M. Imada},
journal= {arXiv preprint arXiv:1107.0835},
year = {2012}
}