Origin of the fragile-to-strong crossover in liquid silica as expressed by its potential-energy landscape

被引：69

作者：

Saksaengwijit, A

Reinisch, J

Heuer, A

机构：

[1] Univ Munster, Inst Phys Chem, D-48149 Munster, Germany

[2] Univ Munster, Int Grad Sch Chem, D-48149 Munster, Germany

来源：

PHYSICAL REVIEW LETTERS | 2004年 / 93卷 / 23期

关键词：

D O I：

10.1103/PhysRevLett.93.235701

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The origin of the fragile-to-strong crossover in liquid silica is characterized in terms of properties of the potential-energy landscape (PEL). Using the standard BKS model [B. W. H. van Beest, G. J. Kramer, and R. A. van Santen, Phys. Rev. Lett. 64, 1955 (1990)] of silica we observe a low-energy cutoff of the PEL. It is shown that this feature of the PEL is responsible for the occurrence of the fragile-to-strong crossover and may also explain the avoidance of the Kauzmann paradox. The number of defects, i.e., deviations from the ideal tetrahedral structure, vanishes for configurations with energies close to this cutoff. This suggests a structural reason for this cutoff.

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页数：4

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