Multi-Wavelength Near-Field Imaging of the Temperature & Current Induced Metal to Insulator Transitions in Ca2RuO4

ORAL

Abstract

Ca2RuO4, a strongly correlated metal oxide and Mott Insulator, exhibits an insulator to metal transition and a large structural distortion along the c-axis concurrently at 365K with a hysteresis of about 30K. In this study, we examine the temperature driven insulator-metal transition (IMT) in single crystals of Ca2RuO4 at the nanoscale with wavelengths ranging from 10 µm to 16 µm, where a strong phonon resonance characterizes the insulating phase. Through this study, we clearly resolve the phonon mode at 16 µm among insulating domains coexisting with the metallic phase, in accord with the far-field optical response of this material. We also resolve a novel pattern of striped phase coexistence emerging on the sub-micron scale that we attribute to the large strain induced by the structural difference between the metallic and insulating phases. We discuss how the development of this stripe pattern spontaneously minimizes strain energy within the crystal. Our interrogation of the metallic and phonon responses of these coexisting phases provides nano-imaging evidence that the temperature and current driven IMTs proceed through fundamentally different microscopic mechanisms.

–

Presenters

  • Rocco Vitalone

    Physics, Columbia University, Columbia University, Department of Physics, Columbia University

Authors

  • Rocco Vitalone

    Physics, Columbia University, Columbia University, Department of Physics, Columbia University

  • Benjamin Aaron Foutty

    Physics, Columbia University, Columbia University, Department of Physics, Columbia University

  • Alexander Swinton McLeod

    Physics, Columbia University, Columbia University, Department of Physics, Columbia University

  • Jedrzej Wieteska

    Columbia University, Physics, Columbia University, Department of Physics, Columbia University

  • Chancal Sow

    Department of Physics, Kyoto University

  • Fumihiko Nakamura

    Department of Education and Creation Engineering, Kurume Institute of Technology

  • 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

  • Abhay Pasupathy

    Columbia University, Physics, Columbia University, Department of Physics, Columbia University in the City of New York, Physics Department, Columbia University, Department of Physics, Columbia University

  • Dimitri Basov

    Department of Physics, Columbia University in the City of New York, Department of Physics, Columbia University, New York 10027, department of physics, columbia university, Department of Physics, Columbia University, Physics, Columbia University, Columbia University