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Silicon carbide polytypes (large unit cells)

by steve_h
Tags: carbide, polytypes, silicon
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Jul14-14, 11:07 AM
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Hello everyone.

I am a Hungarian born Australian theoretical/applied physicist. This is my first post on the forums.

I am aware that silicon carbide crystal occurs in many different crystalline forms. I was wondering if someone here could please point me to a source that catalogs the polytypes in an idiot-proof manner? I basically want the stacking sequences e.g. ABCABCAB... especially for those big bad boy monster unit cells.

This is not for anything serious, just for fun pondering the puzzle of how crystals with such huge unit cells are able to form from what is a very simple basic atomic arrangement. How does the ~100th layer (or whatever it is) know to repeat the pattern?.. Thanks!
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Greg Bernhardt
Jul23-14, 11:34 PM
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I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?
Dr Transport
Jul24-14, 07:42 PM
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PF Gold
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I think there is a Landolt-Borstien volume about SiC. If I remember correctly from my days investigating it, the literature is the best place to start, hundreds of articles to choose from and it only takes a few to get started.

A quick google search turned up enough information to get started. The wikipedia page is very helpful

Jul26-14, 12:32 PM
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Silicon carbide polytypes (large unit cells)

Thank you for the replies. If I find the answer I'll post it here. There is a lot of literature indeed on SiC and narrowing it down to what's relevant to my curiousities is not a trivial task.

But I did find out that SiC gets a brief mention in the classic text by Kittel (on my bookshelf ) that says the long-range order is due to "the presence of spiral steps due to [non-random] dislocations in the growth nucleus". And in chapter 20 there is relevant interesting discussion on spiral crystal growth. Nevertheless the great abundance of polytypes/polymorphs with enormous unit cells (largest ones are 594 layers tall, or about 0.15 micron!) remains an intriguing puzzle for me.

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