On the role of induced impurity potential of β- FeSi2

We have examined the roles of induced impurity potential into β- FeSi2 lattice. Because of the specific band structure, new mechanism through the induced impurity potential are essential for the improvement of optical properties. Expecting the role of induced impurity potential as the source of exciton, we try to apply the successful case of GaP:N to the β- FeSi2. If C atom is substitutionally dissolved in the β- FeSi2 lattice, impurity potential caused by local C atom would generate bound exciton because of the difference of electronegativity between Si and C atoms. The oscillator strength would be expected to be greatly enhanced without any help of phonon because of the formation of Wanier exciton around C with relatively small radius.