doublet

A doublet is a type of crystal defect where two neighboring atoms in a crystal lattice are replaced or missing, creating a localized disruption in the regular arrangement. This defect can affect the material's properties, such as its strength, electrical conductivity, or optical characteristics. In simple terms, imagine a perfectly arranged array of tiles; a doublet would be like two tiles that are slightly different or missing, causing a small but significant irregularity in the pattern. Such defects are common in materials and influence how they behave in various applications.