Scanning Tunneling Spectroscopy in MgB2

Abstract

We present scanning tunneling microscopy measurements of the surface of superconducting MgB2 with a critical temperature of 39K. In zero magnetic field the conductance spectra can be analyzed in terms of the standard BCS theory with a smearing parameter Gamma. The value of the superconducting gap is 5.2 meV at 4.2 K, with no experimentally significant variation across the surface of the sample. The temperature dependence of the gap follows the BCS form, fully consistent with phonon-mediated superconductivity in this novel superconductor. The application of a magnetic field induces strong pair-breaking as seen in the conductance spectra in fields up to 6 T.

4 pages, 4 figures

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• Strongly linked current flow in polycrystalline forms of the new superconductor MgB2
• Boron Isotope Effect in Superconducting MgB${}_2$
• Superconductivity in Dense $Mg{B}_2$ Wires
• Thermodynamic and Transport Properties of Superconducting $M{g}^{10}{B}_2$

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