Topological defects in crystals: a density-wave theory

Raj Lakshmi, M. ; Krishnamurthy, H. R. ; Ramakrishnan, T. V. (1988) Topological defects in crystals: a density-wave theory Bulletin of Materials Science, 10 (1-2). pp. 45-51. ISSN 0250-4707

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A new approach for describing dislocations and other topological defects in crystals, based on the density wave theory of Ramakrishnan and Yussouff is presented. Quantitative calculations are discussed in brief for the order parameter profiles, the atomic configuration and the free energy of a screw dislocation with Burgers vector(b⃗=a/2, a/2, a/2) in a bcc solid. Our results for the free energy of the dislocation in a crystal of size R, when expressed as (λb2/4π) ln(αR/|b|) where λ is the shear elastic constant, yield, for example, the value α1.85 for sodium at its freezing temperature (371°K). The density distribution in the presence of the dislocation shows that the dislocation core has a columnar character. To our knowledge, this study represents the first calculation of dislocation structure, including the core, within the framework of an order parameter theory incorporating thermal effects.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Dislocations; Core Energy and Structure; Topological Defects in Crystals; Density Wave Theory
ID Code:17704
Deposited On:16 Nov 2010 12:49
Last Modified:17 May 2016 02:18

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