In operando evidence of deoxygenation in ionic liquid gating of YBa2Cu3O7-X

Ana M. Perez-Muñoz, Pedro Schio, Roberta Poloni, Alejandro Fernandez-Martinez, Alberto Rivera-Calzada, Julio C. Cezar, Eduardo Salas-Colera, German R. Castro, Joseph Kinney, Carlos Leon, Jacobo Santamaria, Javier Garcia-Barriocanal, Allen M. Goldman

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Field-effect experiments on cuprates using ionic liquids have enabled the exploration of their rich phase diagrams [Leng X, et al. (2011) Phys Rev Lett 107(2):027001]. Conventional understanding of the electrostatic doping is in terms of modifications of the charge density to screen the electric field generated at the double layer. However, it has been recently reported that the suppression of the metal to insulator transition induced in VO2 by ionic liquid gating is due to oxygen vacancy formation rather than to electrostatic doping [Jeong J, et al. (2013) Science 339(6126):1402-1405]. These results underscore the debate on the true nature, electrostatic vs. electrochemical, of the doping of cuprates with ionic liquids. Here, we address the doping mechanism of the high-temperature superconductor YBa2Cu3O7-X (YBCO) by simultaneous ionic liquid gating and X-ray absorption experiments. Pronounced spectral changes are observed at the Cu K-edge concomitant with the superconductor-to-insulator transition, evidencing modification of the Cu coordination resulting from the deoxygenation of the CuO chains, as confirmed by first-principles density functional theory (DFT) simulations. Beyond providing evidence of the importance of chemical doping in electric double-layer (EDL) gating experiments with superconducting cuprates, our work shows that interfacing correlated oxides with ionic liquids enables a delicate control of oxygen content, paving the way to novel electrochemical concepts in future oxide electronics.

Original languageEnglish (US)
Pages (from-to)215-220
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number2
DOIs
StatePublished - Jan 10 2017

Keywords

  • Electric double-layer techniques
  • First-principles density functional theory
  • High-temperature superconductivity
  • Near-edge X-ray absorption spectroscopies
  • Superconductor-insulator transition

How much support was provided by MRSEC?

  • Partial

Reporting period for MRSEC

  • Period 3

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

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