On the electrical conductivity of V2O5 single crystals

The conductivity of pure and doped (Mo, Ti) V2O5 single crystals is measured along the three crystallographic directions in the temperature range 90 to 350° K. For T < 140° K, it is shown that conduction can be considered as a variable range hopping between defect levels, situated in the neighbourhood of the Fermi-level. From combined de and ac measurements, the concentration of localized states is found to be about 1019 cm−3. In the intermediate temperature range 140° K < T < 350° K, the observed anisotropy is explained assuming that conduction is due to hopping along vanadium chains. Attention is drawn to the influence of random potential fluctuations.