Temperature dependence of optical conductivity in double-exchange ferromagnet La1-xSrxMnO3

The optical absorption observed in ferromagnetic metal La_1-xSr_xMnO₃ 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.