Importance of tetrahedral coordination for high-valent transition-metal oxides: YCrO4 as a model system

A. A. Tsirlin, M. G. Rabie, A. Efimenko, Z. Hu, R. Saez-Puche, and L. H. Tjeng
Phys. Rev. B 90, 085106 – Published 8 August 2014

Abstract

We have investigated the electronic structure of the high oxidation state material YCrO4 within the framework of the Zaanen-Sawatzky-Allen phase diagram. While Cr4+-based compounds such as SrCrO3/CaCrO3 and CrO2 can be classified as small-gap or metallic negative-charge-transfer systems, we find using photoelectron spectroscopy that YCrO4 is a robust insulator despite the fact that its Cr ions have an even higher formal valence state of 5+. We reveal using band-structure calculations that the tetrahedral coordination of the Cr5+ ions in YCrO4 plays a decisive role, namely to diminish the bonding of the Cr 3d states with the top of the O 2p valence band. This finding not only explains why the charge-transfer energy remains effectively positive and the material stable, but also opens up a new route to create doped carriers with symmetries different from those of other transition-metal ions.

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  • Received 25 October 2013
  • Revised 19 July 2014

DOI:https://doi.org/10.1103/PhysRevB.90.085106

©2014 American Physical Society

Authors & Affiliations

A. A. Tsirlin1,2, M. G. Rabie1,3,4, A. Efimenko1,4, Z. Hu2, R. Saez-Puche3, and L. H. Tjeng1

  • 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
  • 2National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
  • 3Departamento Quimica Inorganica, Facultad de Ciencas Quimicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
  • 4II. Physikalisches Institut, Universität zu Köln, Zülplicher Straße 77, 50937 Köln, Germany

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Issue

Vol. 90, Iss. 8 — 15 August 2014

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