Instability in the Imma phase of Si
Department of Physics, Florida Atlantic University - Boca Raton, FL 33431-0991, USA
2 IBM Research Division, T. J. Watson Research Center - Yorktown Heights, NY 10598, USA
Accepted: 13 October 2010
The Imma phase of Si is found by first-principles calculations to have unstable states at the two ends of its structural range. These instabilities force first-order transitions to both the β-Sn and the simple hexagonal phase. These transitions occur for the non-vibrating crystal at 96 and 110 kbar, respectively. Two special computational procedures are described that have been developed to find the instabilities.
PACS: 71.15.Nc – Total energy and cohesive energy calculations / 61.50.Ks – Crystallographic aspects of phase transformations; pressure effects / 62.50.-p – High-pressure effects in solids and liquids
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