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Abstract

Measurements of the electric field gradient (efg) at F impurity sites in crystalline silicon and highly oriented pyrolytic graphite (HOPG) have been compared with cluster model calculations using both Hartree-Fock (HF) and density functional theory (DFT) formalisms. Both HF and DFT calculations are consistent with the assignment of interstitial anti-bonding and bond centre sites for the quadrupole frequencies at 23.2 and 35.2 MHz, respectively. In the former case, the F atom is located 1.81 Angstrom along a <111> direction from a silicon atom; in the latter situation the Si-Si bond is found to expand by 1.02 Angstrom from its normal lattice value. It is speculated that a third interaction, which occurs at only the 10 % level, possibly arises from sites associated with a defect or other impurity. To achieve a reduction in cluster size, the completion of dangling bonds with atoms other than hydrogen was investigated. The results were found to be comparable.

Additional information

Authors: SURONO D, JRC Geel (BE);HAMBSCH F J, JRC Geel (BE);MARTIN P W, JRC Geel (BE)
Bibliographic Reference: Article: Hyperfine Interactions, Vol. 96 (1995) pp. 23-25
Record Number: 199510781 / Last updated on: 1995-07-12
Category: PUBLICATION
Original language: en
Available languages: en