Direct evidence of orbital-selective confinement effect of Ru 4<i>d</i> orbitals in SrRuO<sub>3 </sub>ultrathin film

ORAL

Abstract

The electronic structure of SrRuO3 thin film with the thickness from 50 to 1 unit cell (u.c.) is investigated via the resonant inelastic x-ray scattering (RIXS) technique at the O K-edge to unravel the intriguing interplay of orbital and charge degrees of freedom. We found that orbital-selective quantum confinement effect (QCE) induces the splitting of peaks in RIXS spectra of thin films, which corresponds to the charge transfer from O 2p to Ru 4d orbitals. At the same time, we observed a spectral weight transfer from electron-hole continuum to intersite d-d excitation across the metal-to-insulator transition (MIT) occurring between 5 and 4 u.c. samples. From these two clear observations, we conclude that QCE gives rise to a Mott insulating phase in ultrathin SrRuO3 films. Our interpretation of the RIXS spectra is supported by configuration interaction calculations of RuO6 cluster models.

*The work at IBS CCES is supported by Institute of Basic Science in Korea. The work at PSI is supported by the Swiss National Science Foundation through the NCCR MARVEL and the Sinergia network Mott Physics Beyond the Heisenberg Model (MPBH). We also thank Korea Institute for Advanced Study for providing computing resources (KIAS Center for Advanced Computation Linux Cluster System) for this work.

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Presenters

  • Soonmin Kang

    • Seoul National University

Authors

  • Soonmin Kang

    • Seoul National University

  • Yi Tseng

    • Paul Scherrer Institut
    • Swiss Light Source, Paul Scherrer Institut

  • Beom Hyun Kim

    • School of Computational Sciences, Korea Institute for Advanced Study
    • Korea Institute for Advanced Study

  • Seokhwan Yun

    • Seoul National University

  • Byungmin Sohn

    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Seoul National University

  • Bongju Kim

    • Department of physics, Seoul National University
    • Seoul National University

  • Daniel McNally

    • Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institute
    • Swiss Light Source, Paul Scherrer Institut

  • Eugenio Paris

    • Paul Scherrer Institut
    • Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institute
    • Swiss Light Source, Paul Scherrer Institut

  • 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

  • Changyoung Kim

    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Physics and astronomy, Seoul National University
    • Seoul National University
    • CCES-IBS
    • Institute for Basic Science
    • IBS-CCES, Seoul National University

  • Tae Won Noh

    • Department of Physics and Astronomy, Seoul National University
    • Seoul National University

  • Sumio Ishihara

    • Department of Physics, Tohoku University

  • Schmitt Thorsten

    • Paul Scherrer Institut
    • Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institute
    • Paul Scherrer Institute
    • Swiss Light Source, Paul Scherrer Institut

  • 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