Electrical conductivity in single-crystals of vanadium oxide bronzes

Single-crystal electrical conductivity of vanadium oxide bronzes of the type M_xV₂O₅ (β-phase), where M = Li, Na, K has been studied from 300 to 900°K. These compounds are found to exhibit a reversible semiconductor-metal transition along 010] in the region of 340°K. The phase transition observed seems to be caused by vanishing of the activation energy of carrier mobility due to the shift of some vanadium atoms in the planes perpendicular to the B axis.