Independent determination of the two gaps by directional point-contact spectroscopy in MgB_2 single crystals

Abstract

Directional point-contact spectroscopy measurements were performed for the first time in state-of-the-art MgB_2 single crystals. The selective suppression of the superconductivity in the "pi" band by means of a suitable magnetic field allowed separating the partial contribution of each band to the total point-contact conductance. By fitting the partial conductance curves sigma_sigma(V) and sigma_pi(V), we got an independent determination of the two gaps, Delta_sigma and Delta_pi, with a strong reduction of the experimental uncertainty. Their temperature dependence was found to agree well with the predictions of the two-band models for MgB_2.

arXiv comment6 pages, 4 eps figures. References added, abstract rewritten, text slightly changed. Proceedings of the BOROMAG Conference, June 17-19, Genoa, Italy

References in corpus (10)

• Superconductivity of metallic boron in MgB_2
• Beyond Eliashberg superconductivity in MgB2: anharmonicity, two-phonon scattering, and multiple gaps
• Superconductivity of MgB2: Covalent Bonds Driven Metallic
• Electron-phonon interaction in the normal and superconducting states of MgB2
• Evidence for two superconducting energy gaps in MgB2 by point-contact spectroscopy
• Two Gap State Density in MgB${}_2$: A True Bulk Property or A Proximity Effect?
• Two-Band Superconductivity in MgB2
• Multiband model for tunneling in MgB2 junctions
• Temperature and field dependence of the anisotropy of MgB2
• Temperature dependence and anisotropy of the bulk upper critical field H_c2 of MgB_2

Cited by in corpus (6)

• Probing multiband superconductivity by point-contact spectroscopy
• A review of two-band superconductivity: materials and effects on the thermodynamic and reversible mixed-state properties
• Hole superconductivity in Arsenic-Iron compounds
• Materials and mechanisms of hole superconductivity
• Superconducting gap structure and pinning in disordered MgB2 films
• Temperature dependence of the specific heat and the penetration depth of anisotropic-gap BCS superconductors for a factorizable pairing potential