Covalency-driven collapse of strong spin-orbit coupling in face-sharing iridium octahedra

ORAL

Abstract

We report ab-initio density functional theory calculation and Raman scattering results to explore the electronic structure of Ba5CuIr3O12 single crystals. This insulating iridate, consisting of face-sharing IrO6 octahedra forming quasi-one-dimensional chains, cannot be described by the local jeff = 1/2 moment picture commonly adopted for discussing electronic and magnetic properties of iridate compounds with IrO6 octahedra. The shorter Ir-Ir distance in the face-sharing geometry, compared to corner- or edge-sharing structures, leads to strong covalency between neighboring Ir. Then this strong covalency results in the formation of molecular orbitals (MO) at each Ir trimers as the low-energy electronic degree of freedom. The theoretically predicted three-peak structure in the joint density of states, a distinct indication of deviation from thejeff = 1/2 picture, is verified by observing the three-peak structure in the electronic excitation spectrum by Raman scattering.

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Presenters

  • Mai Ye

    Rutgers University, New Brunswick

Authors

  • Mai Ye

    Rutgers University, New Brunswick

  • Heung Sik Kim

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University

  • Jae-Wook Kim

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University, New Jersey

  • Choong-Jae Won

    Max Planck POSTECH/Korea Research Initiative, Pohang University of Science and Technology, Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology,

  • Kristjan Haule

    Rutgers University, New Brunswick, Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University, Department of Physics, Rutgers University, Physics and Astronomy, Rutgers University, Piscataway, NJ, United States

  • David Vanderbilt

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ-08854, USA, Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, New Jersey, Rutgers University, USA, Rutgers Univ, Physics and Astronomy, Rutgers University, Piscataway, NJ, United States, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA

  • Sang-Wook Cheong

    Rutgers University, Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick, Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers University, Center for Quantum Materials Synthesis and Department of Physics and Astronomy, Rutgers, the State University of New Jersey, Department of Physics, Rutgers University, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA, Physics, Rutgers University, Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, New Jersey, Rutgers University, Physics and Astronomy, and Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science, RCEM, Department of Physics and Astronomy, Rutgers U., Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA, Rutgers Center for Emergent Materials

  • Girsh E Blumberg

    Rutgers University, New Brunswick, Department of Physics, Rutgers University