Hyperfine and Superhyperfine Tensors as Probes of the Local Environment of Deep-Level Defect Centers
Abstract
In several recent theoretical studies, we have analyzed the local environment of deep-level defects through comparisons of theoretical and experimental hyperfine tensors. The principal hyperfine interactions sample the distribution of spin density near the center of defect site, and are diagnostics of the local bonding conformation; the smaller hyperfine (superhyperfine) tensors, which are used by couplings of the spin density with nuclei somewhat removed from the center of defect, give valuable information about the embedding of the defect into the extended lattice of its solid-state host. In the present article, we discuss the particular effect of dihedral angles on the second- neighbor superhyperfine interactions in broken-bond defects in silicon and SiO2. This includes such defects centers as the P sub b center at the Si/SiO2 interface, the E' centers which occur in a-SiO2 and quartz, and the D centers of hydrogenated amorphous silicon. The dihedral angle is found to affect the ability of the second-neighbor bonding atomic orbitals to couple to the defect hybrid and participate in the molecular orbital which carries the unpaired electron spin; the result is a significant dependence of second-neighbor superhyperfine splittings on the dihedral angle. Keywords: Hyperfine interactions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 15, 1990
- Accession Number
- ADA227834
Entities
People
- C. T. White
- Michael Cook
Organizations
- United States Naval Research Laboratory