Spiral pits on silicon carbide

ABSTRACT THE dislocation theory of crystal growth1 suggests that the crystal growing at low supersaturation in the presence of a single dislocation is not composed of an infinite number of

layers stacked on each other as ideally considered, but is a helicoid with the dislocation line as its axis and the point of emergence of the dislocation at the top. The observation of a

growth hill in the form of a ‘spiral staircase’ on a number of crystals reported in recent years2 has amply substantiated the theoretical predictions. Silicon carbide crystals have afforded

evidence3 of a large variety of spiral growths, for example, monomolecular as well as microscopic, and interaction of spiral growth due to two or more dislocations of same as well as of

opposite sign. In some cases, hitherto unobserved, silicon carbide crystals exhibit spirally terraced pits. Fig. 1 shows a phase-contrast micrograph of a spirally terraced pit. It is easy to

decide with the fringes of equal chromatic order that this feature is a pit. The step height of this terraced pit as determined from high-dispersion Fizeau fringes corresponds to 27 ± 2 A.,

which is the repeat distance of this crystal identified by X-rays as 33 _R_ (Ramsdell's symbol). Access through your institution Buy or subscribe This is a preview of subscription

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PRECURSORS FOR BASAL DISLOCATION LOOPS IN HEXAGONAL ZIRCONIUM Article Open access 13 November 2020 SITE DEPENDENCE OF SURFACE DISLOCATION NUCLEATION IN CERAMIC NANOPARTICLES Article Open

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AUTHORS AND AFFILIATIONS * Royal Institute of Science, Bombay, 1 V. G. BHIDE Authors * V. G. BHIDE View author publications You can also search for this author inPubMed Google Scholar

RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE BHIDE, V. Spiral Pits on Silicon Carbide. _Nature_ 181, 1006–1007 (1958).

https://doi.org/10.1038/1811006b0 Download citation * Issue Date: 05 April 1958 * DOI: https://doi.org/10.1038/1811006b0 SHARE THIS ARTICLE Anyone you share the following link with will be

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