Nearly free electrons in a 5d delafossite oxide metal

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Pallavi Kushwaha - , Max Planck Institute for Chemical Physics of Solids (Author)
  • Veronika Sunko - , Max Planck Institute for Chemical Physics of Solids, University of St Andrews (Author)
  • Philip J.W. Moll - , Max Planck Institute for Chemical Physics of Solids, ETH Zurich (Author)
  • Lewis Bawden - , University of St Andrews (Author)
  • Jonathon M. Riley - , University of St Andrews, Diamond Light Source (Author)
  • Nabhanila Nandi - , Max Planck Institute for Chemical Physics of Solids (Author)
  • Helge Rosner - , Max Planck Institute for Chemical Physics of Solids (Author)
  • Marcus P. Schmidt - , Max Planck Institute for Chemical Physics of Solids (Author)
  • Frank Arnold - , Max Planck Institute for Chemical Physics of Solids (Author)
  • Elena Hassinger - , Max Planck Institute for Chemical Physics of Solids (Author)
  • Timur K. Kim - , Diamond Light Source (Author)
  • Moritz Hoesch - , Diamond Light Source (Author)
  • Andrew P. MacKenzie - , Max Planck Institute for Chemical Physics of Solids, University of St Andrews (Author)
  • Phil D.C. King - , University of St Andrews (Author)

Abstract

Understanding the role of electron correlations in strong spin-orbit transition-metal oxides is key to the realization of numerous exotic phases including spin-orbit-assisted Mott insulators, correlated topological solids, and prospective new high-temperature superconductors. To date, most attention has been focused on the 5d iridium-based oxides. We instead consider the Pt-based delafossite oxide PtCoO2. Our transport measurements, performed on single-crystal samples etched to well-defined geometries using focused ion beam techniques, yield a room temperature resistivity of only 2.1 microhm•cm (μω-cm), establishing PtCoO2 as the most conductive oxide known. From angle-resolved photoemission and density functional theory, we show that the underlying Fermi surface is a single cylinder of nearly hexagonal cross-section, with very weak dispersion along kz. Despite being predominantly composed of d-orbital character, the conduction band is remarkably steep, with an average effective mass of only 1.14me. Moreover, the sharp spectral features observed in photoemission remain well defined with little additional broadening for more than 500 meV below EF, pointing to suppressed electron-electron scattering. Together, our findings establish PtCoO2 as a model nearly-free-electron system in a 5d delafossite transition-metal oxide.

Details

Original languageEnglish
Article number1500692
JournalScience advances
Volume1
Issue number9
Publication statusPublished - Oct 2015
Peer-reviewedYes
Externally publishedYes

Keywords

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