Spin-orbital-entangled <i>J</i><sub>eff</sub>=1/2 state in 3<i>d</i> transition metal oxide CuAl<sub>2</sub>O<sub>4</sub>

ORAL

Abstract

We show that CuAl2O4 spinel can host a spin-orbital-entangled Jeff=1/2 state. During the long history of the 3d transition metal study, spin-orbit coupling has never been a dominating energy scale. Here we propose on the CuAl2O4 as the first example of a Jeff=1/2 Mott insulator in 3d transition metal compounds. From single crystal X-ray diffraction data, our CuAl2O4 is confirmed to have cubic structure without Jahn-Teller distortion and it is consistent with first-principles total energy calculations. Density functional theory combined with dynamical mean field theory calculations reveal that the Jeff=1/2 state survives the competition with the orbital-momentum-quenched S=1/2 state with the help of strong electron correlation.

*This work was supported by Institute for Basic Science (IBS) in Korea (Grant No. IBS-R009-D1 (CHK, SB), IBS-R024-D1 (AG), IBS-R009-G1 (HC, JGP)), the Basic Science Research Program of the National Research Foundation (NRF) of Korea under Grant No. 2016R1D1A1B03933255 and 2017M3D1A1040828 (HJ).

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Presenters

  • Choong Hyun Kim

    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy
    • Center for Correlated Electron Systems, Institute for Basic Science
    • Department of Physics and Astronomy, Seoul National University
    • Seoul National University
    • CCES-IBS

Authors

  • Choong Hyun Kim

    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy
    • Center for Correlated Electron Systems, Institute for Basic Science
    • Department of Physics and Astronomy, Seoul National University
    • Seoul National University
    • CCES-IBS

  • Hwanbeom Cho

    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy
    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Department of Physics and Astronomy, Seoul National University

  • Santu Baidya

    • Department of Physics and Astronomy, Seoul National University
    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy

  • Vladimir Gapontsev

    • M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences

  • Sergey Streltsov

    • Institute of Metal Physics
    • M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences
    • Ural Federal University, Ekaterinburg, Russia

  • Daniel Khomskii

    • University of Cologne
    • Universität zu Köln
    • University of Cologne, Germany

  • Je-Guen Park

    • Department of Physics and Astronomy, Seoul National University
    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy
    • 2 Center for Correlated Electron Systems, institute for Basic Science; and 3 Department of Physics and Astronomy ,Seoul National University, Seoul, South Korea
    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Seoul National University
    • Department of Physics & Astronomy, Seoul National University, Seoul, Korea
    • Center for Correlated Electron Systems, Institute for Basic Science (IBS), Korea

  • Ara Go

    • Center for Theoretical Physics of Complex Systems, Institute for Basic Science
    • Institute for Basic Science
    • Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS)

  • Hosub Jin

    • Ulsan National Institute of Science and Technology
    • Department of Physics, Ulsan National Institute of Science and Technology (UNIST)