High $T_c$ superconductivity in MgB${}_2$ by nonadiabatic pairing

Abstract

The evidence for the key role of the $\sigma$ bands in the electronic properties of MgB${}_2$ points to the possibility of nonadiabatic effects in the superconductivity of these materials. These are governed by the small value of the Fermi energy due to the vicinity of the hole doping level to the top of the $\sigma$ bands. We show that the nonadiabatic theory leads to a coherent interpretation of $T_c=39$ K and the boron isotope coefficient ${\alpha }_{\mathrm{B}}=0.30$ without invoking very large couplings and it naturally explains the role of the disorder on $T_c$. It also leads to various specific predictions for the properties of MgB${}_2$ and for the material optimization of these type of compounds.

4 revtex pages, 3 eps figures, to appear on Phys. Rev. Lett

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
• Phonon dispersion and electron-phonon coupling in MgB_2 and AlB_2
• The reduced total isotope effect and its implications on the nature of superconductivity in MgB2
• Indication of Superconductivity at 35 K in Graphite-Sulfur Composites
• Nonadiabatic Pauli susceptibility in fullerene compounds
• Implications of reflectance measurements on the mechanism for superconductivity in MgB${}_2$
• Constraints from $T_c$ and the isotope effect for MgB${}_2$

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