Iridates, the New Frontier

Mike Norman, Argonne National Laboratories

Transition metal oxides based on iridium have similarities to the cuprates because of the unique influence of spin-orbit coupling. I will review some recent developments on Sr₂IrO₄, Na₂IrO₃, and particularly Na₄Ir₃O₈. The last is thought to be a quantum spin liquid, with the moments forming a hyperkagome lattice. The nature of its electronic structure, a proposed experiment to detect the existence of spinon Fermi surfaces, and the possibility of superconductivity, will all be discussed.