Electronic temperature, tight-binding

Several structural features, including electron transfer between atoms of different electronegativity, oxygen deficiency, and unsynchronized resonance of valence bonds, as well as tight binding of atoms and the presence of both hypoelectronic and hyperelectronic elements, cooperate to confer metallic properties and high-temperature superconductivity on compounds such as (Sr.Ba.Y.LahCuO,-,. 

These are the only SdH results to date of a M(dmit)2 salt which show clearly that at least for these materials simple tight-binding calculations have to be done with great care. The determination of the real low-temperature crystal structure is essential. Further work for more M(dmit)2 compounds would be needed to get a better understanding of the electronic properties which could give some hints for the important factors governing the appearance of superconductivity in these systems. 

Therefore, superconductivity observed in doped C can be explained in terms of the generalized BCS theory and electron-phonon interaction. The theoretical estimations using a tight-binding method have shown that with an increase in the lattice constant also the density of electronic states around the Fermi level grows. Therefore, the temperature of transition into a superconductive state is increased [60]. These fects are also evidence of the benefit of the traditional BCS mechanism of superconductivity. 

For the salt presenting a room-temperature (RT) conductive regime, it is useful to start from the 1-D tight-binding model. Within this one-electron picture (Fig. 2), independent of bandfilling, one obtains the mean free path A for the charge carriers ... 

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