A New Method of Probing the Phonon Mechanism in Superconductors including MgB${}_2$

Abstract

Weak localization has a strong influence on both the normal and superconducting properties of metals. In particular, since weak localization leads to the decoupling of electrons and phonons, the temperature dependence of resistance (i.e., ${\lambda }_{tr}$) is decreasing with increasing disorder, as manifested by Mooij's empirical rule. In addition, Testardi's universal correlation of $T_c$ (i.e., $\lambda$) and the resistance ratio (i.e., ${\lambda }_{tr}$) follows. This understanding provides a new means to probe the phonon mechanism in superconductors including MgB${}_2$. The merits of this method are its applicability to any superconductors and its reliability because the McMillan's electron-phonon coupling constant $\lambda$ and ${\lambda }_{tr}$ change in a broad range, from finite values to zero, due to weak localization. Karkin et al's preliminary data of irradiated MgB${}_2$ show the Testardi correlation, indicating that the dominant pairing mechanism in MgB${}_2$ is the phonon-mediated interaction.

9 pages, latex, 3 figures

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Cited by in corpus (2)

• Carbon solubility and superconductivity in MgB2
• The three-dimensional Anderson model of localization with binary random potential