Collective modes in Sr2RuO4 measured with momentum-resolved EELS (M-EELS)

ORAL

Abstract

Measurements of the charge susceptibility χ(q,ω) of the high-Tc cuprate Bi-2212 using Momentum-resolved inelastic electron scattering (M-EELS) have shown that bad-metallic behavior can be characterized by a continuum of non-propagating density fluctuations, in stark contrast to the plasmons of simple metals [1]. Here, we report on M-EELS measurements of Sr2RuO4, a bad metal which crosses over to a Fermi Liquid at T=40K. Like Bi-2212, we find that the bad metal phase of Sr2RuO4 exhibits a continuum of density fluctuations. However, below 40K, spectral weight is redistributed to form a plasmon-like excitation around 1.4 eV. Surprisingly, we also discover a coherent low-energy (sub-80meV) 2D acoustic plasmon in the bad metal phase, whose velocity is strongly renormalized from 0.7 to 0.4eV Å below the Fermi liquid crossover, indicating a coupled 2D Fermi Liquid and 3D bad metal in a single solid. We will contrast this coupled system to a closely related ruthenate, the Mott-insulator Ca2RuO4.

[1] M. Mitrano, A. A. Husain, et al. PNAS 115 (21) 5392-5396 (2018)

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Presenters

  • Ali Husain

    University of Illinois at Urbana-Champaign, Department of Physics and Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Physics, University of Illinois at Urbana-Champaign

Authors

  • Ali Husain

    University of Illinois at Urbana-Champaign, Department of Physics and Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Physics, University of Illinois at Urbana-Champaign

  • Matteo Mitrano

    University of Illinois at Urbana-Champaign, Department of Physics and Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Physics, University of Illinois at Urbana-Champaign

  • Melinda Rak

    University of Illinois at Urbana-Champaign, Department of Physics and Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign

  • Samantha Rubeck

    University of Illinois at Urbana-Champaign, Department of Physics and Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign

  • Fumihiko Nakamura

    Department of Education and Creation Engineering, Kurume Institute of Technology

  • Chanchal Sow

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

  • Yoshiteru Maeno

    Department of Physics, Kyoto University, Dept. of Physics, Kyoto University, Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan, Kyoto University, Department of Physics, Graduate School of Science, Kyoto University, Department of Physics, Kyoto University, Kyoto 606-8502, Japan, Department of Physics, Kyoto University, Japan

  • Peter Abbamonte

    University of Illinois, Urbana-Champaign, University of Illinois at Urbana-Champaign, Department of Physics and Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign