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, D. J. Van Harlingen

Research output: Contribution to journalArticle

1 Citation (Scopus)

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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flakes
Superconductivity
Superconducting materials
Energy gap
superconductivity
Spectroscopy
Fermi surface
Gold
Transparency
spectroscopy
Fermi surfaces
Anisotropy
Metals
signatures
Single crystals
gold
Crystals
anisotropy
augmentation
single crystals

All Science Journal Classification (ASJC) codes

  • 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
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, D. 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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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.",
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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

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, D. J.

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

Research output: Contribution to journalArticle

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T1 - Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3

AU - Kurter, C.

AU - Finck, A. D.K.

AU - Huemiller, E. D.

AU - Medvedeva, J.

AU - Weis, A.

AU - Atkinson, J. M.

AU - Qiu, Y.

AU - Shen, L.

AU - Lee, S. H.

AU - Vojta, T.

AU - Ghaemi, P.

AU - Hor, Y. S.

AU - Van Harlingen, D. J.

PY - 2019/1/9

Y1 - 2019/1/9

N2 - 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.

AB - 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.

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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