Theory of phonon-limited resistivity and electron-phonon interaction in higher-stage graphite intercalation compounds

Abstract

The first principle calculations of the basal-plane resistivity and of the electron-phonon coupling constant are presented for higher stage graphite intercalation compounds using a pseudopotential method. On account of the intra- and inter-pocket scatterings in two inequivalent cylindrical Fermi surfaces, the temperature dependence of total resistivity deviates from the ordinary T linear law and follows the T 2 law in the high temperature region, which is consistent with experimental results. It is shown that the present theory also explains other observed characteristics of resistivity such as the existence of a minimum in the resistivity vs. stage curve, and higher mobility compared with those of ordinary metals. Finally, the electron-phonon coupling constant is calculated as a first step towards understanding the mechanism of superconductivity in first stage compounds. It is shown that the electron-phonon coupling constant is fairly large even for second stage compounds and it is comparable with those of weak coupling superconducting metals.