Correlations between Spectra and Resistivity in Transition Metal Oxides

Journal article, 2019

A comparison between photoconductivity spectra and resistivity in two transition metal oxides, La2-xSrxCuO4 and La1-xSrxVO3, is presented. The resistivities ρ(T) for x < 0.05 in the cuprate and x < 0.28 in the vanadate are typical for single electron transfer. For T > 100 K, ρ(T) - ρ(0) ∼T3/2. For higher dopings (x) the cuprate is a superconductor (x < 0.25) and the vanadate an ordinary metal. This tallies with the number of oxidation states and their spins when the electrons transfer locally. The insulator-metal transition and the vanishing of Cooper pairs are discussed in the conclusion.