Local Measurements of the Superconducting Pairing Symmetry in CuxBi2Se3

Topological superconductors represent a newly predicted phase of matter that is topologically distinct from conventional superconducting condensates of Cooper pairs. As a manifestation of their topological character, topological superconductors support solid-state realizations of Majorana fermions a...

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Bibliographic Details
Published in:arXiv.org 2012-11
Main Authors: Levy, Niv, Zhang, Tong, Ha, Jeonghoon, Sharifi, Fred, Talin, A Alec, Young, Kuk, Stroscio, Joseph A
Format: Article
Language:English
Subjects:
BCS theory
Cooper pairs
Energy gap
Fermions
Order parameters
Resistance
Spectroscopic analysis
Spectrum analysis
Superconductivity
Superconductors
Topological superconductors
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Summary:Topological superconductors represent a newly predicted phase of matter that is topologically distinct from conventional superconducting condensates of Cooper pairs. As a manifestation of their topological character, topological superconductors support solid-state realizations of Majorana fermions at their boundaries. The recently discovered superconductor CuxBi2Se3 has been theoretically proposed as an odd-parity superconductor in the time-reversal-invariant topological superconductor class and point-contact spectroscopy measurements have reported the observation of zero-bias conductance peaks corresponding to Majorana states in this material. Here we report scanning tunneling spectroscopy (STS) measurements of the superconducting energy gap in CuxBi2Se3 as a function of spatial position and applied magnetic field. The tunneling spectrum shows that the density of states at the Fermi level is fully gapped without any in-gap states. The spectrum is well described by the Bardeen-Cooper-Schrieffer (BCS) theory with a momentum independent order parameter, which suggests that Cu0.2Bi2Se3 is a classical s-wave superconductor contrary to previous expectations and measurements.
ISSN:2331-8422
DOI:10.48550/arxiv.1211.0267