Localized Orbital Approach to Electronic Structure of Covalent Semiconductors. II. The Impurity States in Silicon

Abstract

The impurity states in Si are investigated theoretically on the basis of a previously proposed formalism, which emphasizes the local environment around the impurity center. The impurity potential is made self-consistent in a finite region surrounding the impurity atom. The difference of substitutional Ga (shallow) and Zn (deep) impurities is discussed from a chemical viewpoint based on atomic properties. The electronic structures of interstitial 3d transition metal impurities Cr, Mn and Fe are calculated for the first time. The obtained result can be interpreted in terms of the difference in chemical bonding between the substitutional and interstitial cases.