The electronic Lorenz number in transition metals at high temperatures

The electronic Lorenz numbers of transition metals are obtained by plotting the thermal conductivity ( lambda ) and electrical conductivity (1/ rho ) data in the form lambda T against T 2 / rho , so that the lattice thermal conductivity can be simultaneously obtained. With a few exceptions, the deviations of the electronic Lorenz number from the Sommerfeld value correspond in sign with the deviations from linearity of the high-temperature electrical resistivity and conform to Kolomoets' theory, which requires that the electronic Lorenz number should generally be less than or more than the Sommerfeld value according to whether the band is nearly full or almost empty respectively.