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Title: Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca 2 RuO 4

Abstract

The Mott insulator Ca 2RuO 4 is the subject of much recent attention following reports of emergent nonequilibrium steady states driven by applied electric fields or currents. In this paper, we carry out infrared nano-imaging and optical-microscopy measurements on bulk single crystal Ca 2RuO 4 under conditions of steady current flow to obtain insight into the current-driven insulator-tometal transition. We observe macroscopic growth of the current-induced metallic phase, with nucleation regions for metal and insulator phases determined by the polarity of the current flow. A remarkable metal-insulator-metal microstripe pattern is observed at the phase front separating metal and insulator phases. The microstripes have orientations tied uniquely to the crystallographic axes, implying a strong coupling of the electronic transition to lattice degrees of freedom. Theoretical modeling further illustrates the importance of the current density and confirms a submicron-thick surface metallic layer at the phase front of the bulk metallic phase. Our work confirms that the electrically induced metallic phase is nonfilamentary and is not driven by Joule heating, revealing remarkable new characteristics of electrically induced insulator-metal transitions occurring in functional correlated oxides.

Authors:
 [1];  [2];  [2];  [1];  [3];  [1];  [1];  [1];  [4];  [5];  [6];  [3];  [7];  [7];  [8];  [9];  [2];  [10];  [7];  [1]
  1. Stony Brook Univ., NY (United States)
  2. Columbia Univ., New York, NY (United States)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Chinese Academy of Sciences (CAS), Beijing (China)
  5. Texas A & M Univ., College Station, TX (United States)
  6. Brookhaven National Lab. (BNL), Upton, NY (United States)
  7. Kyoto Univ. (Japan)
  8. Kurume Inst. of Technology, Fukuoka (Japan)
  9. Nagoya Univ. (Japan)
  10. Columbia Univ., New York, NY (United States); The Flatiron Inst., New York, NY (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1494869
Alternate Identifier(s):
OSTI ID: 1496044
Grant/Contract Number:  
AC02-05CH11231; SC0012704; SC0012375
Resource Type:
Journal Article: Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 9; Journal Issue: 1; Journal ID: ISSN 2160-3308
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Zhang, Jiawei, McLeod, Alexander S., Han, Qiang, Chen, Xinzhong, Bechtel, Hans A., Yao, Ziheng, Gilbert Corder, S. N., Ciavatti, Thomas, Tao, Tiger H., Aronson, Meigan, Carr, G. L., Martin, Michael C., Sow, Chanchal, Yonezawa, Shingo, Nakamura, Fumihiko, Terasaki, Ichiro, Basov, D. N., Millis, Andrew J., Maeno, Yoshiteru, and Liu, Mengkun. Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca2RuO4. United States: N. p., 2019. Web. doi:10.1103/physrevx.9.011032.
Zhang, Jiawei, McLeod, Alexander S., Han, Qiang, Chen, Xinzhong, Bechtel, Hans A., Yao, Ziheng, Gilbert Corder, S. N., Ciavatti, Thomas, Tao, Tiger H., Aronson, Meigan, Carr, G. L., Martin, Michael C., Sow, Chanchal, Yonezawa, Shingo, Nakamura, Fumihiko, Terasaki, Ichiro, Basov, D. N., Millis, Andrew J., Maeno, Yoshiteru, & Liu, Mengkun. Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca2RuO4. United States. doi:10.1103/physrevx.9.011032.
Zhang, Jiawei, McLeod, Alexander S., Han, Qiang, Chen, Xinzhong, Bechtel, Hans A., Yao, Ziheng, Gilbert Corder, S. N., Ciavatti, Thomas, Tao, Tiger H., Aronson, Meigan, Carr, G. L., Martin, Michael C., Sow, Chanchal, Yonezawa, Shingo, Nakamura, Fumihiko, Terasaki, Ichiro, Basov, D. N., Millis, Andrew J., Maeno, Yoshiteru, and Liu, Mengkun. Fri . "Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca2RuO4". United States. doi:10.1103/physrevx.9.011032.
@article{osti_1494869,
title = {Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca2RuO4},
author = {Zhang, Jiawei and McLeod, Alexander S. and Han, Qiang and Chen, Xinzhong and Bechtel, Hans A. and Yao, Ziheng and Gilbert Corder, S. N. and Ciavatti, Thomas and Tao, Tiger H. and Aronson, Meigan and Carr, G. L. and Martin, Michael C. and Sow, Chanchal and Yonezawa, Shingo and Nakamura, Fumihiko and Terasaki, Ichiro and Basov, D. N. and Millis, Andrew J. and Maeno, Yoshiteru and Liu, Mengkun},
abstractNote = {The Mott insulator Ca2RuO4 is the subject of much recent attention following reports of emergent nonequilibrium steady states driven by applied electric fields or currents. In this paper, we carry out infrared nano-imaging and optical-microscopy measurements on bulk single crystal Ca2RuO4 under conditions of steady current flow to obtain insight into the current-driven insulator-tometal transition. We observe macroscopic growth of the current-induced metallic phase, with nucleation regions for metal and insulator phases determined by the polarity of the current flow. A remarkable metal-insulator-metal microstripe pattern is observed at the phase front separating metal and insulator phases. The microstripes have orientations tied uniquely to the crystallographic axes, implying a strong coupling of the electronic transition to lattice degrees of freedom. Theoretical modeling further illustrates the importance of the current density and confirms a submicron-thick surface metallic layer at the phase front of the bulk metallic phase. Our work confirms that the electrically induced metallic phase is nonfilamentary and is not driven by Joule heating, revealing remarkable new characteristics of electrically induced insulator-metal transitions occurring in functional correlated oxides.},
doi = {10.1103/physrevx.9.011032},
journal = {Physical Review. X},
issn = {2160-3308},
number = 1,
volume = 9,
place = {United States},
year = {2019},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/physrevx.9.011032

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Works referenced in this record:

A fast, high-endurance and scalable non-volatile memory device made from asymmetric Ta2O5?x/TaO2?x bilayer structures
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