Electromagnetic and superconducting properties

If carriers of opposite sign, i.e., electrons and holes, are present, these 

A natural objection to such an approach is the problem of whether conduction electrons in the given compounds can be considered to be quasi-free. As is known, the conductivity of refractory compounds is comparable to that of the corresponding transition metals and is considerably less than the conductivity of typical nontransition metals. In the case of high densities of states at the Fermi level this indicates a partial localisation of electrons, which appears when the crystal contains impurities, vacancies and other types of translational symmetry disturbances. There are indications, however, that partial localization of conduction electrons does not lead to qualitatively different relationships between the 

For the same conditions A a, conductivity in the nonperiodic potential is expressed by the Kubo-Greenwood relationship  

Taking into account the Kubo-Greenwood relationship 

If we assume that N( ) = const x ( — p) , where v 1 (which is the case with refractory compounds of NaCl-type structure with eight valence electrons per primitive cell), then 

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