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For example, in cubic close-packed crystals, the stacking sequence of a twin boundary would be ABCABCBACBA. On planes of single crystals, steps between atomically flat terraces can also be regarded as planar defects. It has been shown that such defects and their geometry have significant influence on the adsorption of organic molecules [16]
Comparison of fcc and hcp lattices, explaining the formation of stacking faults in close-packed crystals. In crystallography, a stacking fault is a planar defect that can occur in crystalline materials. [1] [2] Crystalline materials form repeating patterns of layers of atoms. Errors can occur in the sequence of these layers and are known as ...
A perfect crystal is a crystal that contains no point, line, or planar defects. [1] There are a wide variety of crystallographic defects . The hypothetical concept of a perfect crystal is important in the basic formulation of the third law of thermodynamics .
Some defects in the boundary, such as steps and ledges, may also offer alternative mechanisms for atomic transfer. Grain growth can be inhibited by second phase particles via Zener pinning . Since a high-angle boundary is imperfectly packed compared to the normal lattice it has some amount of free space or free volume where solute atoms may ...
An antiphase domain (APD) is a type of planar crystallographic defect in which the atoms within a region of a crystal are configured in the opposite order to those in the perfect lattice system. Throughout the entire APD, atoms sit on the sites typically occupied by atoms of a different species.
An edge dislocation is a defect where an extra half-plane of atoms is introduced midway through the crystal, distorting nearby planes of atoms. When enough force is applied from one side of the crystal structure, this extra plane passes through planes of atoms breaking and joining bonds with them until it reaches the grain boundary.
The boundary between crystal segments is called a composition surface or, if it is planar, a composition plane. The composition plane is often, though not always, parallel to the twin law plane of a reflection law. If this is the case, the twin plane is always parallel to a possible crystal face. [2]
Most natural diamonds contain extended planar defects in the <100> lattice planes, which are called "platelets". Their size ranges from nanometers to many micrometers, and large ones are easily observed in an optical microscope via their luminescence. [83]