Metallization of quasi-two-dimensional Mott insulator CaIrO3 with S=1/2 spins

We report on three attempts to metallize a S = 1/2 antiferromagnetic Mott insulator CaIrO3 with the quasi-two-dimensional post-perovskite structure. By controlling the dimensionality and the electron filling, we can successfully drive a metal-insulator transition, while an insulating state is robust against the applied pressure. These results are compared with related experiments for the post-perovskite Mg0.9Fe0.1SiO4, the layered perovskite Ca2RuO4, and high-T-c cuprates. The interplay between spin, charge, and orbital degrees of freedom is discussed. (C) 2009 Elsevier B.V. All rights reserved.