Nanoscopic diffusion of water on a topological insulator

Anton Tamtögl*, Marco Sacchi, Nadav Avidor, Irene Calvo-Almazán, Peter S. M. Townsend, Martin Bremholm, Philip Hofmann, John Ellis, William Allison

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

The microscopic motion of water is a central question, but gaining experimental information about the interfacial dynamics of water in fields such as catalysis, biophysics and nanotribology is challenging due to its ultrafast motion, and the complex interplay of inter-molecular and molecule-surface interactions. Here we present an experimental and computational study of the nanoscale-nanosecond motion of water at the surface of a topological insulator (TI), Bi2Te3. Understanding the chemistry and motion of molecules on TI surfaces, while considered a key to design and manufacturing for future applications, has hitherto been hardly addressed experimentally. By combining helium spin-echo spectroscopy and density functional theory calculations, we are able to obtain a general insight into the diffusion of water on Bi2Te3. Instead of Brownian motion, we find an activated jump diffusion mechanism. Signatures of correlated motion suggest unusual repulsive interactions between the water molecules. From the lineshape broadening we determine the diffusion coefficient, the diffusion energy and the pre-exponential factor.
Original languageEnglish
Article number278
JournalNature Communications
Volume11
Issue number1
Early online date14 Jan 2020
DOIs
Publication statusPublished - 14 Jan 2020

Keywords

  • Topological insulator
  • Diffusion coefficient
  • Water sorption
  • Density functional theory
  • Spin echo experiments
  • Friction
  • Atom scattering
  • Atom surface interaction

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Fields of Expertise

  • Advanced Materials Science

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