Electron transport mechanism in the pseudogap system: quasicrystals, approximants and amorphous alloys

We have analyzed the electron transport mechanism in quasicrystals and their approximants in diverse classes as being typical of the pseudogap systems by employing the Mott conductivity formula. The transport mechanism is divided into two regimes dominated by the mean free path effect and the g2-dependent electronic structure effect, the latter of which is specific to the pseudogap system. The critical resistivity ρo is defined as the resistivity across which the former is taken over by the latter. It is shown that the ρ–T dependence of quasicrystals and their approximants can be well interpreted in terms of the critical resistivity line drawn in the resistivity versus the g-parameter diagram.