Optical reflectivity spectra measured on cleaved surfaces of La1-xSrxMnO3:: Evidence against extremely small Drude weight

Optical reflectivity spectra were measured on cleaved surfaces of La1-xSrxMnO3 single crystals (0 less than or equal to x less than or equal to 0.30). The optical conductivity sigma(omega) shows, keeping single-component nature, an incoherent-to-coherent crossover with a spin polarization of conducting epsilon(g) electrons. The sigma(omega) spectrum of the ferromagnetic-metal La0.70Sr0.30MnO3 is characterized by a pronounced Drude-like component with large spectral A eight below similar to 1.6 eV, which yields a large effective carrier number N-eff* consistent with the results of other techniques. The present result demonstrates that the previous result of "small Drude weight" is due to a deterioration of the sample surface, at least for the heavily doped region.