@article{d08c2c211a1945e79e7775a0f68948c7,
title = " Conductance Spectroscopy of Exfoliated Thin Flakes of Nb x Bi 2 Se 3 ",
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.",
keywords = "Andreev reflection spectroscopy, Majorana bound states, Topological superconductivity, doped topological insulators, exfoliated Nb Bi Se, p-wave pairing symmetry",
author = "C. Kurter and Finck, {A. D.K.} and Huemiller, {E. D.} and J. Medvedeva and A. Weis and Atkinson, {J. M.} and Y. Qiu and L. Shen and Lee, {S. H.} and T. Vojta and P. Ghaemi and Hor, {Y. S.} and {Van Harlingen}, {D. J.}",
note = "Funding Information: C.K., A.D.K.F., E.D.H., and D.J.V.H. would like to acknowledge funding by Microsoft Station-Q. E.D.H. and D.J.V.H. acknowledge funding from the NSF Grant DMR 17-10437. T.V. acknowledges funding from the NSF Grant DMR-1506152. P.G. acknowledges support from the NSF CREST Center for Interface Design and Engineered Assembly of Low Dimensional systems (IDEALS) and the NSF Grant HRD-1547830. Y.S.H. acknowledges funding from the NSF Grant DMR-1255607. J.E.M. acknowledges the computational support provided by XSEDE and NERSC. For the device fabrication, we acknowledge the use of the facilities of the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana−Champaign, supported by the Department of Energy. We would like to thank Jessica Terbush for assistance of imaging the samples. We are thankful for helpful discussions with Fan Zhang. Funding Information: C.K., A.D.K.F., E.D.H., and D.J.V.H. would like to acknowledge funding by Microsoft Station-Q. E.D.H. and D.J.V.H. acknowledge funding from the NSF Grant DMR 17-10437. T.V. acknowledges funding from the NSF Grant DMR- 1506152. P.G. acknowledges support from the NSF CREST Center for Interface Design and Engineered Assembly of Low Dimensional systems (IDEALS) and the NSF Grant HRD- 1547830. Y.S.H. acknowledges funding from the NSF Grant DMR-1255607. J.E.M. acknowledges the computational support provided by XSEDE and NERSC. For the device fabrication, we acknowledge the use of the facilities of the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana?Champaign, supported by the Department of Energy. We would like to thank Jessica Terbush for assistance of imaging the samples. We are thankful for helpful discussions with Fan Zhang. Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",
year = "2019",
month = jan,
day = "9",
doi = "10.1021/acs.nanolett.8b02954",
language = "English (US)",
volume = "19",
pages = "38--45",
journal = "Nano letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "1",
}