Optical Evidence of Anderson-Mott Localization in FeSi

摘要: We have investigated the electrodynamic response of single-crystalline FeSi over a frequency range from d.c. to 105 cm-1. At low frequencies, we found evidence for an Anderson-Mott localization behaviour low-temperature optical conductivity, while at high frequencies excitation spectrum resembles that conventional semiconductor. The missing spectral weight below gap energy is redistributed around edge, in disagreement with previous claims based on measurements.