Importance of thermal disorder and electronic occupation for temperature dependence of optical conductivity in FeSi and MnSi

摘要: The spectral weight (SW) for optical transitions in FeSi and MnSi are calculated as a function of temperature by means linear muffin-tin orbital--local density approximation band calculations. main effects, caused structural disorder electronic Fermi-Dirac distribution, act oppositely on the $T$ dependence SW, while variation magnetic moment has only minor effect. calculations agree with experimental findings an increasing SW decreasing $T$. results can be understood from change structure disorder.