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@ARTICLE{Leis:1041581,
      author       = {Leis, Arthur and Schleenvoigt, Michael and Moors, Kristof
                      and Soltner, Helmut and Cherepanov, Vasily and Schüffelgen,
                      Peter and Mussler, Gregor and Grützmacher, Detlev and
                      Voigtländer, Bert and Lüpke, Felix and Tautz, F. Stefan},
      title        = {{P}robing edge state conductance in ultra-thin topological
                      insulator films},
      publisher    = {arXiv},
      reportid     = {FZJ-2025-02320},
      year         = {2022},
      abstract     = {Quantum spin Hall (QSH) insulators have unique electronic
                      properties, comprising a band gap in their two-dimensional
                      interior and one-dimensional spin-polarized edge states in
                      which current flows ballistically. In scanning tunneling
                      microscopy (STM), the edge states manifest themselves as a
                      localized density of states. However, there is a significant
                      research gap between the observation of edge states in
                      nanoscale spectroscopy, and the detection of ballistic
                      transport in edge channels which typically relies on
                      transport experiments with microscale lithographic contacts.
                      Here, we study few-layer films of the three-dimensional
                      topological insulator (Bi$_{x}$Sb$_{1-x})_2$Te$_3$, for
                      which a topological transition to a two-dimensional
                      topological QSH insulator phase has been proposed. Indeed,
                      an edge state in the local density of states is observed
                      within the band gap. Yet, in nanoscale transport experiments
                      with a four-tip STM, 2 and 3 quintuple layer films do not
                      exhibit a ballistic conductance in the edge channels. This
                      demonstrates that the detection of edge states in
                      spectroscopy can be misleading with regard to the
                      identification of a QSH phase. In contrast, nanoscale
                      multi-tip transport experiments are a robust method for
                      effectively pinpointing ballistic edge channels, as opposed
                      to trivial edge states, in quantum materials.},
      keywords     = {Mesoscale and Nanoscale Physics (cond-mat.mes-hall) (Other)
                      / FOS: Physical sciences (Other)},
      cin          = {PGI-3 / PGI-9 / ITE},
      cid          = {I:(DE-Juel1)PGI-3-20110106 / I:(DE-Juel1)PGI-9-20110106 /
                      I:(DE-Juel1)ITE-20250108},
      pnm          = {5213 - Quantum Nanoscience (POF4-521)},
      pid          = {G:(DE-HGF)POF4-5213},
      typ          = {PUB:(DE-HGF)25},
      doi          = {10.48550/ARXIV.2204.03753},
      url          = {https://juser.fz-juelich.de/record/1041581},
}