Some Solid-State Studies of Tungsten Trioxide and Their Significance to Tungsten Bronze Theory

Abstract

The Hall voltage, resistivity, and thermoelectric power have been measured on single crystals of tungstic oxide (γ phase: 10° to 330°C). The electrical transport properties can be explained quantitatively on the basis of a shallow donor model (E_D=0.04 eV) in which carrier mobility is limited primarily by polar scattering from optical mode lattice vibrations. The interaction between electron and phonon is describable by the perturbation theory of Howarth and Sondheimer (replacing the effective mass by the polaron mass) or by the intermediate coupling theory of Lee, Low, and Pines. The model has been extended successfully to calculate the thermal and composition dependences of resistivity and Seebeck coefficient for the cubic sodium tungsten bronzes.