Structure of the electronic states in FeSb$_{2}$ according to optical spectroscopy and band calculations

The electronic structure and optical properties of the binary intermetallic compound FeSb$_{2}$ have been studied. The band structure was calculated in the local density approximation, which showed the existence of a narrow $\sim$0.3 eV gap in the energy spectrum of this material. The spectral characteristics were studied by ellipsometric method in the wavelength range of 0.22–18 $\mu$m. It is shown that the experimental optical conductivity of the compound in the region of interband transitions is satisfactorily interpreted in the framework of the calculations of the density of electronic states.