This title appears in the Scientific Report :
2020
Please use the identifier:
http://hdl.handle.net/2128/25102 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.101.245413 in citations.
Parasitic conduction channels in topological insulator thin films
Parasitic conduction channels in topological insulator thin films
Thin films of topological insulators (TI) usually exhibit multiple parallel conduction channels for the transport of electrical current. Aside from the topologically protected surface states (TSS), parallel channels may exist, namely, the interior of the not-ideally insulating TI film, the interface...
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Personal Name(s): | Just, Sven (Corresponding author) |
---|---|
Lüpke, Felix / Cherepanov, Vasily / Tautz, F. Stefan / Voigtländer, Bert | |
Contributing Institute: |
Quantum Nanoscience; PGI-3 |
Published in: | Physical Review B Physical review / B, 101 101 (2020 2020) 24 24, S. 245413 245413 |
Imprint: |
Woodbury, NY
Inst.
2020
|
DOI: |
10.1103/PhysRevB.101.245413 |
Document Type: |
Journal Article |
Research Program: |
Controlling Electron Charge-Based Phenomena |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.101.245413 in citations.
Thin films of topological insulators (TI) usually exhibit multiple parallel conduction channels for the transport of electrical current. Aside from the topologically protected surface states (TSS), parallel channels may exist, namely, the interior of the not-ideally insulating TI film, the interface layer to the substrate, and the substrate itself. To be able to take advantage of the auspicious transport properties of the TSS, the influence of the parasitic parallel channels on the total current transport has to be minimized. Because the conductivity of the interior (bulk) of the thin TI film is difficult to access by measurements, we propose here an approach for calculating the mobile charge carrier concentration in the TI film. To this end, we calculate the near-surface band bending using parameters obtained experimentally from surface-sensitive measurements, namely, (gate-dependent) four-point resistance measurements and angle-resolved photoelectron spectroscopy. While in most cases another parameter in the calculations, i.e., the concentration of unintentional dopants inside the thin TI film, is unknown, it turns out that in the thin-film limit the band bending is largely independent of the dopant concentration in the film. Thus, a well-founded estimate of the total mobile charge carrier concentration and the conductivity of the interior of the thin TI film proves possible. Since the interface and substrate conductivities can be measured by a four-probe conductance measurement prior to the deposition of the TI film, the total contribution of all parasitic channels, and therefore also the contribution of the vitally important TSS, can be determined reliably. |