Defect and electronic structure of TiSi2 thin films produced by co-sputterings. Part II: Chemical bonding and electron energy-loss near-edge structures

Citation
T. Mizoguchi et al., Defect and electronic structure of TiSi2 thin films produced by co-sputterings. Part II: Chemical bonding and electron energy-loss near-edge structures, ACT MATER, 49(12), 2001, pp. 2321-2328
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
ACTA MATERIALIA
ISSN journal
1359-6454 → ACNP
Volume
49
Issue
12
Year of publication
2001
Pages
2321 - 2328
Database
ISI
SICI code
1359-6454(20010717)49:12<2321:DAESOT>2.0.ZU;2-6
Abstract
Differences in the bonding mechanisms of amorphous, C49 and C54 TiSi2 have been studied by the combination of experimental Si-L-23 edge electron energ y-loss near-edge structures (ELNES) and first-principles calculations using model clusters composed of 48 to 69 atoms. A half-filled core-hole is put into the central Si atom of the cluster in order to include the core-hole e ffects. Agreement between experiment and theory is quite satisfactory in th e first 20 eV; the difference in width of the first peak; between different phases is well reproduced. The width of the first peak can be related to t he covalency of the compound. The total covalency of the compounds was quan tified using covalent bond density (CBD), defined by the number of bonds an d the bond overlap populations computed in this study. The total CBD of the C54 phase is found to be 14% greater than that of the C49 phase. This is c onsistent with the conclusion reached by analysis of the Si-L-23, edge ELNE S. The amorphous phase displayed similar Si-L-23 edge ELNES to that of the C49 phase. This is suggestive of the presence of C49-like bonding structure s in the amorphous TiSi2, as exemplified by the presence of Si-Si bonds sho rter than 2.5 Angstrom. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd.. All rights reserved.