Charge-transfer energy in iridates: A hard x-ray photoelectron spectroscopy study

ORAL

Abstract

We have investigated the electronic structure of iridates in the double perovskite crystal structure containing either Ir4+ or Ir5+ using hard x-ray photoelectron spectroscopy. The experimental valence band spectra can be well reproduced using tight-binding calculations including only the Ir 5d, O 2p, and O 2s orbitals with parameters based on the downfolding of the density-functional band structure results. We found that, regardless of the A and B cations, the A2BIrO6 iridates have essentially zero O 2p to Ir 5d charge-transfer energies. Hence double perovskite iridates turn out to be extremely covalent systems with the consequence being that the magnetic exchange interactions become very long ranged, thereby hampering the materialization of the long-sought Kitaev physics. Nevertheless, it still would be possible to realize a spin-liquid system using the iridates with a proper tuning of the various competing exchange interactions.
These results have been published in Phys. Rev. B (DOI: /10.1103/PhysRevB.102.045119)

*The research was partially supported by the Deutsche Forschungsgemeinschaft through SFB 1143 (Project-Id 247310070) and Grant No. 320571839. We acknowledge support from the Max Planck-POSTECH-Hsinchu Center for Complex Phase Materials.

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Presenters

  • Daisuke Takegami

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids (MPI CPfS)

Authors

  • Daisuke Takegami

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids (MPI CPfS)

  • Deepa Kasinathan

    • Max Planck Institute for Chemical Physics of Solids

  • Klaus K. Wolff

    • Max Planck Institute for Chemical Physics of Solids

  • Simone Altendorf

    • Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
    • Max Planck Institute for Chemical Physics of Solids

  • Chun-Fu Chang

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids (MPI CPfS)

  • Katharina Hoefer

    • Max Planck Institute for Chemical Physics of Solids

  • Anna Melendez-Sans

    • Max Planck Institute for Chemical Physics of Solids

  • Yuki Utsumi

    • Max Planck Institute for Chemical Physics of Solids

  • Federico Meneghin

    • Max Planck Institute for Chemical Physics of Solids

  • Duy Ha

    • Max Planck Institute for Chemical Physics of Solids

  • Chien-Han Yen

    • Max Planck Institute for Chemical Physics of Solids

  • Kai Chen

    • Helmoltz-Zentrum Berlin fuer Materialien und Energie
    • Institute of Physics II, University of Cologne

  • Chang-Yang Kuo

    • National Synchrotron Radiation Research Center (NSRRC)

  • Yen-Fa Liao

    • National Synchrotron Radiation Research Center (NSRRC)

  • Ku-Ding Tsuei

    • National Synchrotron Radiation Research Center (NSRRC)

  • Ryan Morrow

    • Leibniz Institute for Solid State and Materials Research IFW Dresden

  • Sabine Wurmehl

    • Leibniz Institute for Solid State and Materials Research IFW Dresden
    • Leibniz Institute for Solid State and Materials Research

  • Bernd Büchner

    • Leibniz Institute for Solid State and Materials Research IFW Dresden
    • Leibniz Institute for Solid State and Materials Research
    • Leibniz Institute for Solid State and Materials Research Dresden

  • Beluvalli-Eshwarappa Prasad

    • Max Planck Institute for Chemical Physics of Solids

  • Martin Jansen

    • Max Planck Institute for Solid State Research

  • Alexander Komarek

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids (MPI CPfS)
    • Max Planck Institute

  • Philipp Hansmann

    • Department of Physics, University of Erlangen-Nuremberg, Germany
    • Institut für Theoretische Physik, Friedrich-Alexander-University Erlangen-Nuernberg
    • Max Planck Institute for Chemical Physics of Solids
    • Max-Planck Institute for Chemical Physics of Solids

  • Liu Tjeng

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
    • Max Planck Institute for Chemical Physics of Solids (Dresden, Germany)
    • Max Planck Institute for Chemical Physics of Solids (MPI CPfS)
    • Max-Planck Institute for Chemical Physics of Solids