Bi-Arrhenius Diffusion and Surface Trapping of Li+8 in Rutile TiO2

A. Chatzichristos, R. M. L. McFadden, M. H. Dehn, S. R. Dunsiger, D. Fujimoto, V. L. Karner, I. McKenzie, G. D. Morris, M. R. Pearson, M. Stachura, J. Sugiyama, J. O. Ticknor, W. A. MacFarlane, and R. F. Kiefl
Phys. Rev. Lett. 123, 095901 – Published 29 August 2019

Abstract

We report measurements of the diffusion rate of isolated ion-implanted Li+8 within 120nm of the surface of oriented single-crystal rutile TiO2 using a radiotracer technique. The α particles from the Li8 decay provide a sensitive monitor of the distance from the surface and how the depth profile of Li8 evolves with time. The main findings are that the implanted Li+ diffuses and traps at the (001) surface. The T dependence of the diffusivity is described by a bi-Arrhenius expression with activation energies of 0.3341(21) eV above 200 K, whereas at lower temperatures it has a much smaller barrier of 0.0313(15) eV. We consider possible origins for the surface trapping, as well the nature of the low-T barrier.

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  • Received 4 March 2019

DOI:https://doi.org/10.1103/PhysRevLett.123.095901

© 2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

A. Chatzichristos1,2,*, R. M. L. McFadden2,3, M. H. Dehn1,2, S. R. Dunsiger4, D. Fujimoto1,2, V. L. Karner2,3, I. McKenzie5,6, G. D. Morris5, M. R. Pearson5, M. Stachura5, J. Sugiyama7,8,9, J. O. Ticknor2,3, W. A. MacFarlane2,3,5, and R. F. Kiefl1,2,5,†

  • 1Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
  • 2Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
  • 3Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
  • 4Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
  • 5TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
  • 6Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
  • 7Toyota Central Research and Development Laboratories, Inc., Nagakute, Aichi 480-1192, Japan
  • 8Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
  • 9CROSS Neutron Science and Technology Center, 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan

  • *aris.chatzichristos@alumni.ubc.ca
  • kiefl@triumf.ca

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Issue

Vol. 123, Iss. 9 — 30 August 2019

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