Topological defects in crystals: A density-wave theory

Lakshmi, Raj M and Murthy, Krishna HR and Ramakrishnan, TV (1988) Topological defects in crystals: A density-wave theory. In: Bulletin of Materials Science, 10 (1-2). pp. 45-51.

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Abstract

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 b = (a/2, a/2,a/2 ) in a bcc solid. Our results for the free energy of the dislocation in a crystal of sizeR, when expressed as (λb 2/4π) ln (αR/|b|) whereλ is the shear elastic constant, yield, for example, the valueα ⋍ 1·85 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:	Journal Article
Publication:	Bulletin of Materials Science
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	Dislocations;core energy and structure;topological defects in crystals;density wave theory.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	12 Oct 2010 11:05
Last Modified:	12 Oct 2010 11:09
URI:	http://eprints.iisc.ac.in/id/eprint/33056

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