Electrodynamics near the metal-to-insulator transition in V3 O5

The electrodynamics near the metal-to-insulator transitions induced, in V3O5 single crystals, by both temperature (T) and pressure (P) has been studied by infrared spectroscopy. The T and P dependence of the optical conductivity may be explained within a polaronic scenario. The insulating phase at ambient T and P corresponds to strongly localized small polarons. Meanwhile the T-induced metallic phase at ambient pressure is related to a liquid of polarons showing incoherent dc transport, in the P-induced metallic phase at room T strongly localized polarons coexist with partially delocalized ones. The electronic spectral weight is almost recovered, in both the T- and P-induced metallization processes, on an energy scale of 1 eV, thus supporting the key role of electron-lattice interaction in the V3O5 metal-to-insulator transitions.