High-Temperature Measurements of the Electron Hall Mobility in the Alkali Halides

Using a modification of the Redfield technique, the electronic Hall mobility has been measured over the temperature range from 150 to 400 K in nine alkali halides made photoconducting by either x irradiation or electrolytic coloration. The measurements indicate that in all cases the Hall mobility decreases much more sharply with increasing temperature than wide-band optical-phonon scattering theories would predict. Preliminary consideration of the effects of polaron-band narrowing yield results which agree well with the temperature dependence of the data.