Evidence for variable range hopping conductivity in the ordered quasicrystal i-AlPdRe

We Show that the conductivity of the quasicrystal i-AlPdRe follows a Mott's variable range hopping conduction law sigma(T) = sigma(0) exp -(T-0/T)(1/4) in the temperature range 20-600 mK. The i-AlPdRe phase thus behaves like disordered insulators at very low temperature. We find a very low activation term T-0 similar to 1 mK, which is an indication of a large localization length xi, in accordance with the vicinity to the metal-insulator transition. This is the first time that a pure Mott's law is observed at very low temperature in a structurally ordered compound made of metallic elements.