Characteristic Features of the Physicochemical Structure of Chromium Disilicide

Abstract

An electron-valence scheme of chromium disilicide is proposed on the basis of a comparison of a crystallochemical analysis of this compound with its electrical and magnetic properties. The bond scheme in CrSi₂ explains satisfactorily the anisotropy shown by the electrical and thermal conductivity of its single crystals. The anisotropy of the thermoelectric power of CrSi₂ is explained by the fact that holes with a different effective mass are always present because of the heterodesmic nature of the chemical bonds (Cr-Si, Si-Si). On the basis of an analysis of the characteristic features of the change of electrical properties in the “intrinsic” conduction region, it is concluded that the free 3d level of the chromium atoms in CrSi₂ acts as the acceptor and is situated, as regards energy, between the edge of the valence band and the bottom of the conduction band. From analysis of the experimental and calculated density of CrSi₂, it is proposed that the high (10²⁰ cm⁻³) hole density in stoichiometric samples at room temperature is due to the “molecular” imperfection of the crystal lattice.

“Semiconductors,” pp. 291–298 (see page 3).