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Publication Citation: Experimental Evidence for s-Wave Pairing Symmetry in Superconducting Cu_{x}Bi_{2}Se_{3} Single Crystals Using a Scanning Tunneling Microscope

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Author(s): Niv Levy; Tong Zhang; Jeonghoon Ha; Fred Sharifi; Alec Talin; Young Kuk; Joseph A. Stroscio;
Title: Experimental Evidence for s-Wave Pairing Symmetry in Superconducting Cu_{x}Bi_{2}Se_{3} Single Crystals Using a Scanning Tunneling Microscope
Published: March 12, 2013
Abstract: Topological superconductors (TS) are a newly predicted phase of matter which is topologically distinct from conventional superconducting condensates of Cooper pairs. As a manifestation of its topological character, TS supports massless itinerant quasi-particles on the boundary, which are solid-state realizations of Majorana fermions. The recently discovered superconductor CuxBi2Se3 has been theoretically proposed as an odd-parity superconductor in the time-reversal-invariant TS class. 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 strongly suggests that Cu0.2Bi2Se3 is a classical s-wave superconductor contrary to previous expectations.
Citation: Physical Review Letters
Volume: 110
Issue: 11
Keywords: Topological superconductors;scanning tunneling microscopy;scanning tunneling spectroscopy
Research Areas: Characterization, Nanometrology, and Nanoscale Measurements
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