Transport properties of the quasi-one-dimensional crystal nb4te17i4

We report an investigation of the transport properties of the quasi-one-dimensional crystals Nb4Te17I4, and we compare them with the properties of (NbSe4)3I which has more regular structure in the chain direction. Electrical resistivity at room temperature is ρ=5 Ωm, and no transition was observed in the range 100K<T<340K. By lowering temperature ρ(T) follows an activation law. Thermal conductivity κ(T) shows an exponential behavior at low temperatures. By increasing temperature around 180K the measured thermal conductivity is very closed to the minimum possible thermal conductivity for this system.