Letter abstract
Nature Materials 2, 739 - 743 (2003)
Published online: 12 October 2003 | doi:10.1038/nmat994
Subject Categories: Glasses | Semiconductors | Computation, modelling and theory
Liquid–liquid phase transition in supercooled silicon
Srikanth Sastry1 & C. Austen Angell2
Abstract
Silicon in its liquid and amorphous forms occupies a unique position among amorphous materials. Obviously important in its own right, the amorphous form is structurally close to the group of 4–4, 3–5 and 2–6 amorphous semiconductors that have been found to have interesting pressure-induced semiconductor-to-metal phase transitions1, 2. On the other hand, its liquid form has much in common, thermodynamically, with water and other 'tetrahedral network' liquids that show density maxima3, 4, 5, 6, 7. Proper study of the 'liquid–amorphous transition', documented for non-crystalline silicon by both experimental and computer simulation studies8, 9, 10, 11, 12, 13, 14, 15, 16, 17, may therefore also shed light on phase behaviour in these related materials. Here, we provide detailed and unambiguous simulation evidence that the transition in supercooled liquid silicon, in the Stillinger–Weber potential18, is thermodynamically of first order and indeed occurs between two liquid states, as originally predicted by Aptekar10. In addition we present evidence to support the relevance of spinodal divergences near such a transition, and the prediction3 that the transition marks a change in the liquid dynamic character from that of a fragile liquid to that of a strong liquid.
- Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur Campus, Bangalore 560064, India
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA
Correspondence to: Srikanth Sastry1 e-mail: sastry@jncasr.ac.in
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