Direct evidence of orbital-selective confinement effect of Ru 4d orbitals in SrRuO3 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.

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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