Evolution of energetics and bonding of compact self-interstitial clusters in Si

A. Bongiorno; L. Colombo; F. Cargnoni; C. Gatti; M. Rosati

doi:doi:10.1209/epl/i2000-00313-4

DOI: 10.1209/epl/i2000-00313-4

Europhys. Lett., 50 (5), p. 608 (2000)

Evolution of energetics and bonding of compact
self-interstitial clusters in Si

A. Bongiorno ¹ - L. Colombo ² - F. Cargnoni ³ - C. Gatti ³ - M. Rosati ⁴

¹ IRRMA - Ecublens, 1015 Lausanne, Switzerland
² INFM and Dipartimento di Fisica, Università di Cagliari
09042 Monserrato (CA), Italy
³ CNR-CSRSRC - via Golgi 19, 20133 Milano, Italy
⁴ CASPUR - Piazzale A. Moro 5, 00185 Roma, Italy

(Received 18 November 1999; accepted in final form 27 March 2000)

PACS :
61.72.Bb - Theories and models of crystal defects
61.72.Ji - Point defects (vacancies, interstitials, color centers, etc.) and defect clusters
71.15.Fv - Atomic- and molecular-orbital methods (including tight-binding approximation, valence-bond method, etc.)

luciano.colombo@dsf.unica.it

Abstract:

The growth of self-interstitial clusters in crystalline Si is investigated by semi-empirical tight-binding molecular dynamics. The equilibrium configuration of each n-interstitial cluster $(n=2\mbox{--}11)$ has been obtained by adding one more dumbbell defect to the previously relaxed (n-1) SI cluster in the series. We find an evolutionary path from compact (n<5) to elongated $(n\ge 5)$ clusters. We relate the shape evolution of clusters to the changes in their atomic coordination and bonding properties, using first principles structure calculations and a topological analysis of their associated electron densities.

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