Charge dynamics in the Kondo insulator Ce₃Bi₄Pt₃

We report the reflectivity and optical conductivity of the Kondo insulator Ce3Bi4Pt3. For temperatures less than 100 K, depletion of the conductivity below about 300 cm-1 signifies the development of a charge gap. The temperature dependence of the disappearance of the spectral weight scales with the quenching of the Ce 4f moments. © 1994.