Crystallographic defect

A crystallographic defect is an interruption of the regular patterns of arrangement of atoms or molecules in crystalline solids.

Strict limits for how small a point defect is are generally not defined explicitly.

In metallic materials, b is aligned with close-packed crystallographic directions and its magnitude is equivalent to one interatomic spacing.

It is the presence of dislocations and their ability to readily move (and interact) under the influence of stresses induced by external loads that leads to the characteristic malleability of metallic materials.

Deep-level transient spectroscopy has been used for studying the electrical activity of dislocations in semiconductors, mainly silicon.

Basically, this means that if you track the crystal orientation around the line defect, you get a rotation.

[15] A successful mathematical classification method for physical lattice defects, which works not only with the theory of dislocations and other defects in crystals but also, e.g., for disclinations in liquid crystals and for excitations in superfluid 3He, is the topological homotopy theory.

Electron microscopy of antisites (a, Mo substitutes for S) and vacancies (b, missing S atoms) in a monolayer of molybdenum disulfide . Scale bar: 1 nm. [ 1 ]
Schematic illustration of some simple point defect types in a monatomic solid
Schematic illustration of defects in a compound solid, using GaAs as an example.
An edge dislocation is shown. The dislocation line is presented in blue, the Burgers vector b in black.
Origin of stacking faults: Different stacking sequences of close-packed crystals