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

Rocco Vitalone; Benjamin Aaron Foutty; Alexander Swinton McLeod; Jedrzej Wieteska; Chancal Sow; Fumihiko Nakamura; Yoshiteru Maeno; Abhay Pasupathy; Dimitri Basov

Multi-Wavelength Near-Field Imaging of the Temperature & Current Induced Metal to Insulator Transitions in Ca<sub>2</sub>RuO<sub>4</sub>

ORAL

Abstract

Ca₂RuO_4, 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.

March 5, 2019, 3:42 PM – March 5, 2019, 3:54 PM

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