Conductance Spectroscopy of Exfoliated Thin Flakes of NbxBi2Se3

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.

doi:10.1021/acs.nanolett.8b02954

Conductance Spectroscopy of Exfoliated Thin Flakes of Nb_xBi₂Se₃

Journal Article · Mon Nov 26 23:00:00 EST 2018 · Nano Letters

DOI:https://doi.org/10.1021/acs.nanolett.8b02954· OSTI ID:1543686

^[1]; Finck, A. D. K. ^[2]; Huemiller, E. D. ^[3]; Medvedeva, J. ^[4]; Weis, A. ^[3]; Atkinson, J. M. ^[3]; Qiu, Y. ^[4]; Shen, L. ^[4]; Lee, S. H. ^[4]; Vojta, T. ^[4]; Ghaemi, P. ^[5]; Hor, Y. S. ^[4]; Van Harlingen, D. J. ^[3]

Missouri Univ. of Science and Technology, Rolla, MO (United States); Univ. of Illinois at Urbana-Champaign, IL (United States)
Univ. of Illinois at Urbana-Champaign, IL (United States); IBM Thomas J. Watson Research Center, Yorktown Heights, NY (United States)
Univ. of Illinois at Urbana-Champaign, IL (United States)
Missouri Univ. of Science and Technology, Rolla, MO (United States)
City College of New of CUNY, New York, NY (United States); Department of Physics, Graduate Center of CUNY, New York, NY (United States)

We study unconventional superconductivity in exfoliated single crystals of a promising three-dimensional (3D) topological superconductor candidate, Nb-doped Bi₂Se₃ 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 Bi₂Se₃ 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 Bi₂Se₃. Lastly, we observe signatures of multiple superconducting energy gaps, which could originate from multiple Fermi surfaces reported earlier in bulk crystals.

View Accepted Manuscript (DOE)

Research Organization:: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Organization:: USDOE; NSF

OSTI ID:: 1543686

Journal Information:: Nano Letters, Journal Name: Nano Letters Journal Issue: 1 Vol. 19; ISSN 1530-6984

Publisher:: American Chemical SocietyCopyright Statement

Country of Publication:: United States

Language:: English

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Classifying Induced Superconductivity in Atomically Thin Dirac-Cone Materials No authors listed Condensed Matter, Vol. 4, Issue 3 https://doi.org/10.3390/condmat4030083	journal	September 2019

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Related Subjects

36 MATERIALS SCIENCE
Andreev reflection spectroscopy
Majorana bound states
Materials Science
chemistry
doped topological insulators
electrical conductivity
energy
exfoliated NbxBi2Se3
group theory
magnetic properties
other topics
p-wave pairing symmetry
physics
science & technology
superconductors
topological superconductivity