Point-contact spectroscopy of Al- and C-doped MgB2. Superconducting energy gaps and scattering studies

Abstract

The two-band/two-gap superconductivity in aluminium and carbon doped MgB${}_2$ has been addressed by the point-contact spectroscopy. Two gaps are preserved in all samples with $T_c^{\prime }s$ down to 22 K. The evolution of two gaps as a function of the critical temperature in the doped systems suggest the dominance of the band-filling effects but for the increased Al-doping the enhanced interband scattering approaching two gaps must be considered. The magnetic field dependences of the Andreev reflection excess currents as well as zero-energy density of states determined from the experimental data are used to analyze the intraband scattering. It is shown, that while the C-doping increases the intraband scattering in the $\pi$-band more rapidly then in the $\sigma$ band, the Al-doping does not change their relative weight.

8 pages, incl. 6 figures

References in corpus (26)

• Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors
• Systematic effects of carbon doping on the superconducting properties of Mg(B${}_{1-x}$C${}_x$)${}_2$
• Vortex Imaging in the pi-Band of Magnesium Diboride
• Band filling and interband scattering effects in MgB${}_2$: C vs Al doping
• Specific heat of single crystal MgB_2: a two-band superconductor with two different anisotropies
• Carbon doping of superconducting magnesium diboride
• Definitive experimental evidence for two-band superconductivity in MgB2
• Fermi surface topology and the upper critical field in two-band superconductors - application to MgB2
• Mixed state of a dirty two-band superconductor: application to MgB_2
• Al substitution in MgB2 crystals: influence on superconducting and structural properties
• Anisotropy of the upper critical field in superconductors with anisotropic gaps. Anisotropy parameters of MgB2
• The different development of the anisotropic upper critical field in MgB2 by aluminum and carbon doping
• Toward one-band superconductivity in MgB2
• Thermodynamics of Two - Band Superconductors: The Case of MgB${}_2$
• Evidence for Single-gap Superconductivity in Mg(B_{1-x}C_x)_2 Single Crystals with x=0.132 from Point-Contact Spectroscopy
• Carbon-substitution dependent multiple superconducting gap of MgB${}_2$: a "sub-meV" resolution photoemission study
• Retention of Two-Band Superconductivity in Highly Carbon-Doped MgB2
• Systematic study of the two band/two gap superconductivity in carbon-substituted MgB2 by point-contact spectroscopy
• Two band/two gap superconductivity in carbon-substituted MgB2 evidenced by point-contact spectroscopy
• Anisotropy parameters of superconducting MgB${}_2$
• Scanning Tunneling Spectroscopy in MgB 2
• Point-contact spectroscopy of MgB2
• Influence of Al doping on the critical fields and gap values in magnesium diboride single crystals
• Comment on: "Band Filling and Interband Scattering Effects in MgB2: Carbon versus Aluminium Doping"
• Electron diffusivities in MgB2 from point contact spectroscopy
• Excess current in point contacts on two-band superconductor MgB${}_2$ in magnetic field

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• Effects of magnetic and non-magnetic doping on the vortex lattice in MgB${}_2$
• Two-bands superconductivity with intra- and interband pairing for synthetic superlattices
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