Observation of Energy Gap in FeGa₃

Abstract

The existence of an energy gap around the Fermi energy is established experimentally for the intermetallic compound FeGa₃. ⁵⁷Fe Mössbauer spectra measured at room temperature confirmed the absence of magnetic ordering. The temperature dependence of magnetic susceptibility, χ(T), measured on single-crystalline samples showed diamagnetic behavior below room temperature, and it increased exponentially with temperature above 500 K. Fitting to the high-temperature data yielded an energy gap Δ of 0.29–0.45 eV. Valence-band x-ray photoemission spectra directly revealed the energy gap, the size of which was estimated to be Δ\\lesssim0.8 eV. These results agree with the prediction by recent band calculations.