Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3

C. Kurter, A. D.K. Finck, E. D. Huemiller, J. Medvedeva, A. Weis, J. M. Atkinson, Y. Qiu, L. Shen, S. H. Lee, T. Vojta, P. Ghaemi, Y. S. Hor, Dale J Van Harlingen

Research output: Contribution to journalArticle

Abstract

We study unconventional superconductivity in exfoliated single crystals of a promising three-dimensional (3D) topological superconductor candidate, Nb-doped Bi 2 Se 3 through differential conductance spectroscopy and magneto-transport. The strong anisotropy of the critical field along the out-of-plane direction suggests that the thin exfoliated flakes are in the quasi-2D limit. Normal metal-superconductor (NS) contacts with either high or low transparencies made by depositing gold leads onto Nb-doped Bi 2 Se 3 flakes both show significant enhancement in zero bias conductance and coherence dips at the superconducting energy gap. Such behavior is inconsistent with conventional Blonder-Tinkham-Klapwijk theory. Instead, we discuss how our results are consistent with p-wave pairing symmetry, supporting the possibility of topological superconductivity in Nb-doped Bi 2 Se 3 . Finally, we observe signatures of multiple superconducting energy gaps, which could originate from multiple Fermi surfaces reported earlier in bulk crystals.

Original languageEnglish (US)
Pages (from-to)38-45
Number of pages8
JournalNano letters
Volume19
Issue number1
DOIs
StatePublished - Jan 9 2019

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Spectroscopy
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Keywords

  • Andreev reflection spectroscopy
  • Majorana bound states
  • Topological superconductivity
  • doped topological insulators
  • exfoliated Nb Bi Se
  • p-wave pairing symmetry

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Kurter, C., Finck, A. D. K., Huemiller, E. D., Medvedeva, J., Weis, A., Atkinson, J. M., ... Van Harlingen, D. J. (2019). Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3 Nano letters, 19(1), 38-45. https://doi.org/10.1021/acs.nanolett.8b02954

Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3 . / Kurter, C.; Finck, A. D.K.; Huemiller, E. D.; Medvedeva, J.; Weis, A.; Atkinson, J. M.; Qiu, Y.; Shen, L.; Lee, S. H.; Vojta, T.; Ghaemi, P.; Hor, Y. S.; Van Harlingen, Dale J.

In: Nano letters, Vol. 19, No. 1, 09.01.2019, p. 38-45.

Research output: Contribution to journalArticle

Kurter, C, Finck, ADK, Huemiller, ED, Medvedeva, J, Weis, A, Atkinson, JM, Qiu, Y, Shen, L, Lee, SH, Vojta, T, Ghaemi, P, Hor, YS & Van Harlingen, DJ 2019, ' Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3 ', Nano letters, vol. 19, no. 1, pp. 38-45. https://doi.org/10.1021/acs.nanolett.8b02954
Kurter C, Finck ADK, Huemiller ED, Medvedeva J, Weis A, Atkinson JM et al. Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3 Nano letters. 2019 Jan 9;19(1):38-45. https://doi.org/10.1021/acs.nanolett.8b02954
Kurter, C. ; Finck, A. D.K. ; Huemiller, E. D. ; Medvedeva, J. ; Weis, A. ; Atkinson, J. M. ; Qiu, Y. ; Shen, L. ; Lee, S. H. ; Vojta, T. ; Ghaemi, P. ; Hor, Y. S. ; Van Harlingen, Dale J. / Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3 In: Nano letters. 2019 ; Vol. 19, No. 1. pp. 38-45.
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