Nano-scale ultrafast dynamics of Mott Insulating Ca<sub>2-x</sub>Sr<sub>x</sub>RuO<sub>4</sub>

ORAL

Abstract

Ca2RuO4 is a correlated transition metal oxide that exhibits a Mott transition (IMT) concurrent with a symmetry preserving Jahn-Teller distortion (JT) at 350 K. This strong coupling between the electronic and structural transitions in Ca2RuO4 makes studying the role played by individual degrees of freedom nontrivial. Since the Mott insulating state relies on a half-filled band, it is instructive to use optical photo-excitation to disrupt orbital ordering and the associated Mott State without directly perturbing the crystal structure. Using spectroscopic measurements with sub-picosecond temporal resolution and nano-scale spatial resolution, we interrogate the interplay and level of codependency of the JT and IMT via thermal cycling through the transition and electron-hole injection. Through the thermodynamic pathway, we observe phase coexistence in the form of a stripe phase existing at the domain wall between bulk insulating and metallic regions. Through the ultrafast carrier injection pathway, we observe the formation of localized mid-gap states that lead to enhanced absorption in the time domain with no spatial inhomogeneity. We posit that these mid-gap states become localized via polaronic features related to the local perturbation of the JT distortion.

*NDSEG Fellowship

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Presenters

  • Rocco Vitalone

    • Columbia University
    • Columbia Univ

Authors

  • Rocco Vitalone

    • Columbia University
    • Columbia Univ

  • Aaron Sternbach

    • Department of Physics, Columbia University
    • Columbia University
    • Columbia Univ

  • Ben Foutty

    • Stanford University

  • Alexander S McLeod

    • Columbia University
    • Department of Physics, Columbia University
    • Columbia Univ

  • Chanchal Sow

    • Kyoto University

  • Denis Golez

    • Simons Foundation
    • Jozef Stefan Institute and Center for Computational Quantum Physics, Flatiron Institute

  • Fumihiko Nakamura

    • Department of Education and Creation Engineering, Kurume Institute of Technology, Fukuoka 830-0052, Japan
    • Kurume Institute of Technology

  • Yoshiteru Maeno

    • Physics, Kyoto University
    • Kyoto University
    • Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
    • Kyoto Univ
    • Department of Physics, Kyoto University

  • Abhay Narayan

    • Department of Physics, Columbia University
    • Physics, Columbia University
    • Columbia Univ
    • Department of Physics, Columbia University, New York, New York 10027, USA
    • Columbia University

  • Antoine Georges

    • Collège de France, Paris and Flatiron Institute, New York
    • Simons Foundation
    • Center for Computational Quantum Physics, Flatiron Institute
    • Center of Computational Quantum Physics, Flatiron Institute, New York City, USA
    • College de France

  • Andrew Millis

    • Columbia University
    • Department of Physics, Columbia University
    • Flatiron Institute
    • Columbia Univ
    • Center for Computational Quantum Physics, Flatiron Institute
    • Flatiron Institute; Columbia Univ.
    • Columbia University and Center for Computational Quantum Physics, Flatiron Institute

  • Dmitri Basov

    • Columbia University
    • Department of Physics, Columbia University
    • Physics, Columbia University
    • Columbia Univ