Lattice relaxations at substitutional impurities in semiconductors

✍ Scribed by Matthias Scheffler

• Publisher: Elsevier Science
• Year: 1987
• Weight: 1018 KB
• Volume: 146
• Category: Article
• ISSN: 0378-4363
• DOI: 10.1016/0378-4363(87)90060-x

✦ Synopsis

The positions of the crystal nuclei in the surrounding of substitutional impurities in Si and GaAs have been calculated using density-functional theory together with the local-density approximation for exchange and correlation and the total-energy gradient approach.

These investigations give a qualitative explanation of the mechanism which drives the impurity-induced lattice relaxations as well as quantitative predictions of relaxation amplitudes up to far away from the defect. Both, the electronic screening charge at the impurity, and the long-range distortion pattern of the nuclei are found to be highly anisotropic, propagating mostly along the zigzag bonding chains of the ( 110) planes. Comparisons of the calculated distortions for Si : As' and GaAs: S' with two recent EXAFS analyses and for Si : S' with an EPR analysis show good agreement.