New experimental and analytical techniques are used to derive information on the electronic band structure of SiP2, a semimetal having a pyrite structure. The ir reflectivity can be described by a two-carrier model having effective charge density to mass ratios of 0.152 and 0.0273 with relaxation times of 1.07 and 0.66 × 10-14 sec, respectively. This model yields a dc conductivity of 1.07 × 106 mho/m in agreement with measured values. Interband transitions at 1.97 eV, 2.69 eV, 3.45 eV, 3.95 eV, and 4.42 eV were defined from structure in the imaginary part of the dielectric constant and from piezoreflectance data.
John R. Barkley, "Measurement and Analysis of the Reflectance Spectra of SiP2," Appl. Opt. 11, 1928-1935 (1972)