Temperature Dependence of the Cyclotron Mass of an Electron Polaron in AgBr

We report measurements of the cyclotron effective mass of AgBr as a function of the temperature, which show a temperature dependence given by $m^{*}\mathrm{}\left(T\right)=m^{*}\mathrm{}\left(0\right)+\mu \exp (-\frac{\theta }{T})$. The quantities $\mu$ and $m^{*}\mathrm{}\left(0\right)\mathrm{}$ are expressed in units of the free electron mass; $\mu$ is sample dependent and on the order of 1, $m^{*}\mathrm{}\left(0\right)\mathrm{}$ is between 0.286 and 0.289, and the activation temperature $\theta$ is ≅80°K. This result can be interpreted as arising from a resonant electronphonon interaction between an electron in the conduction band of the crystal and a bound impurity state mediated by a LA phonon.