Complex stacking fault

Using the constructed potentials the y-surface for the (111) plane was calculated. (For more details see Girshick and Vitek 1995). T e lowest energy minimum on this surface corresponds to the ideal Llo structure. However, there are three different metastable stacking fault type defects on (111) the antiphase boundary (APB), the complex stacking fault (CSF) and the superlattice intrinsic stacking fault (SISF). The displacements... 

We should briefly consider the changes that happen to the low Miller index planes of gold these have been deeply researched, and are quite complex, so a simple summary must suffice. Gold is the only element the (111) surface of which reconstructs under UHV conditions.50 The new structure is described by a complex stacking-fault-domain model in which there are areas (or domains) of both fee and eph (close-packed hexagonal) structure its Miller index is (23 x V3), and 23 atoms occupy positions that would normally be taken by 22 atoms, and in consequence the new surface is... 

CSF complex stacking fault f.c.t. face-centered tetragonal... 

Zeolite structures sometimes remain unsolved for a long time, because of either their complexity, the minute size of the crystallites or the presence of defects or impurities. One extreme example of stacking disorder is provided by zeolite beta [1,2], Different stacking sequences give rise to two polymorphs (A and B) in zeolite beta that always coexist in very small domains in the same crystal. Not only do the small domains make the peaks in the powder X-ray diffraction pattern broad and thereby exacerbate the reflection overlap problem, but the presence of stacking faults also gives rise to other features in the diffraction pattern that further complicate structure solution. 

Recently, Rocha and Zanchet have studied the defects in silver nanoprisms in some detail and have shown that the internal structure can be very complex with many twins and stacking faults [107]. These defects are parallel to each other and the flat 111 face of the nanoprism, subdividing it into lamellae which are stacked in a <111> direction, and are also present in the silver seeds. In that paper, it was demonstrated how the planar defects in the <111> direction could give rise to local hexagonally close-packed (hep) regions. These could in turn explain the 2.50 A lattice fringes that are observed in <111> orientated nanofrisms, which have hitherto been attributed to formally forbidden 1/3(422 reflections as mentioned above. 

One problem with any material with a layered structure is that these materials often exhibit stacking faults. As the structure is the same in two dimensions, it can easily be disrupted to produce the wrong stacking sequence. As the layer sequence becomes more complex, the hkeh-hood of stacking faults increases. Many Ruddlesden-Popper phases exist for = 1, but as n increases the number of known phases decreases. This is likely to be related to the increased formation of stacking faults, which prevents isolation of the perfectly ordered phase for characterization purposes. 

It is now generally accepted that the correct structural characterization of the complex Si(lll) (7x7) structure is the dimer-adatom stacking fault model proposed by Takayanagi and coworkers (Takayanagi et al., 1985a, b). This structure consists of twelve Si adatoms located upon of a layer of Si dimers with vacancies at the vertices of the (7x7) unit cell. The physical origin of the tendency of this surface to form such a complex reconstruction is believed to be the result of the competition between two factors the... 

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