RE: slabs and supercells

 Sent to CCL by: "Ojwang, J.G.O." [j.g.o.ojwang[a]tue.nl]
 I'll be brief and to the point, plus use a layman's language.
 When you want to study the surface of a material then the pragmatic way to go is
 to terminate one part of a periodic crystal thus creating a slab. We view slab
 as a structure whose periodicity has been terminated along one direction, that
 direction being treated as the surface of the crystal.
 In the case of supercells....a supercell is in simple words a build up of a
 primitive cell along the three crystallographic axes by addition of more atoms.
 Supercells are important in the study of defects and dopants. Clearly when you
 dope a material it is only by a few percentage and as such if you want to be as
 exact as possible in treating a problem pertaining to defects and doping then
 you must build a supercell.
 I hope that answers your questions without much of the jargons used in the
 field.
 Ojwang JGO.
 More contributions are welcome
 -----Original Message-----
 From:	CCL [mailto:owner-chemistry[a]ccl.net]
 Sent:	Mon 7/11/2005 2:08 PM
 To:	Ojwang, J.G.O.
 Cc:
 Subject:	CCL: slabs and supercells
 Sent to CCL by: may abdelghani <may01dz_-_yahoo.fr>
 Hello, CCLer
 What we mean by slabs and supercells, and why we study
 them?
 best regards
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