Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 56: Focus Session: Electronic Properties of Spin-Orbit Driven Oxides
TT 56.1: Invited Talk
Wednesday, April 2, 2014, 09:30–10:00, HSZ 03
Exotic Magnetism of Jeff=1/2 Iso-Spins in Complex Ir Oxides — •Hidenori Takagi — Department of Physics, University of Tokyo, Tokyo, Japan — Max Planck Institute for Solid State Research, Stuttgart, Germany
In 5d Iridium oxides, a large spin-orbit coupling of 0.5 eV, inherent to heavy 5d elements, is not small as compared with other relevant electronic parameters including Coulomb U, transfer t and crystal field splitting D, which gives rise to a variety of exotic magnetic ground states. In the layered perovskite Sr2IrO4, spin-orbital Mott state with Jeff=1/2 is realized due to the novel interplay of those energy scales [1, 2]. Despite the strong entanglement of spin and orbital degrees of freedom, surprisingly isotropic, two-dimensional Heisenberg character of Jeff=1/2 iso-spins was observed in Sr2IrO4 with 180 deg Ir-O-Ir bonds, by the recent resonant magnetic x-ray diffuse scattering and the magnetic susceptibility measurements [3]. Complex Na-Ir oxides with honeycomb and more recently identified hyper-honeycomb lattices, where 90 deg Ir-O-Ir bonds are realized, are candidates for Kitaev spin liquid. Such exotic magnetism was recently shown to be tailored using super-lattice structure [4]. In this talk, we review these phases of interest.
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