Nanoscale Near-Field Tomography of Surface States on (Bi(0.5)b(0.5))(2)Te-3

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Fabian Mooshammer
  • Fabian Sander
  • Markus Huber
  • Martin Zizlsperger
  • Helena Weigand
  • Markus Plankl
  • Christian Weyrich
  • Martin Lanius
  • Jörn Kampmeier
  • Gregor Mussler
  • Detlev Grützmacher
  • Tyler Cocker
  • Rupert Huber


Three-dimensional topological insulators (TIs) have attracted tremendous interest for their possibility to host massless Dirac Fermions in topologically protected surface states (TSSs), which may enable new kinds of high-speed electronics. However, recent reports have outlined the importance of band bending effects within these materials, which results in an additional two-dimensional electron gas (2DEG) with finite mass at the surface. TI surfaces are also known to be highly inhomogeneous on the nanoscale, which is masked in conventional far-field studies. Here, we use near-field microscopy in the mid-infrared spectral range to probe the local surface properties of custom-tailored (Bi0.5Sb0.5)2Te3 structures with nanometer precision in all three spatial dimensions. Applying nanotomography and nanospectroscopy, we reveal a few-nanometer-thick layer of high surface conductivity and retrieve its local dielectric function without assuming any model for the spectral response. This allows us to directly distin...

Bibliographical metadata

Original languageEnglish
Pages (from-to)7515-7523
Number of pages9
JournalNano Letters
Issue number12
Early online date13 Nov 2018
Publication statusPublished - 12 Dec 2018

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