NATURE OF THE BAND-GAP OF POLYCRYSTALLINE BETA-FESI2 FILMS

We present experimental evidence for the indirect nature of the beta-FeSi2 gap. We furthermore show, by analyzing the temperature dependence of the direct gap by means of a thermodynamic empirical model, that beta-FeSi2 exhibits an unusually strong electron-phonon interaction. We finally deduce the electron-hole mobility from our measurements.