Temperature dependence of optical conductivity in double-exchange ferromagnetLa1−xSrxMnO3

The optical absorption observed in ferromagnetic metal ${\mathrm{La}}_{1-x}{\mathrm{Sr}}_x{\mathrm{MnO}}_3$ shows a strong temperature dependence. Assuming that the temperature dependence comes mainly from the spontaneous magnetization, we study theoretically how the optical conductivity is affected by the decrease of spontaneous magnetization. The coherent-potential approximation is used to describe the effect of $t_{2g}$ spin disorder on the optical conductivity, which consists of intraband and interband transitions within $e_g$ bands. The result explains well some important features of the experimental data.