Novel Insulator and Superconductivity in a 5d Electron System of Iridium Oxides(Research)

Abstract

We have studied a three-orbital Hubbard model to understand the detailed electronic structure of 5d transition metal oxide Sr_2IrO_4. We have shown that the large spin-orbit coupling of 5d electrons induces the novel insulating state, characterized by an effective total angular momentum J_<eff>=1/2. This material is found to be located between Slater and Mott insulators. We have also proposed that the novel superconductivity is induced by electron doping for Sr_2IrO_4.