What is v-center in crystal?

A v-center, or vacancy center, in a crystal is a point defect that occurs when an atom is missing from its regular lattice site in the crystal structure. This vacancy can affect the material's electronic and optical properties, as it creates localized states in the band structure. V-centers are often important in the study of semiconductors and can influence phenomena such as conductivity and luminescence. They play a significant role in various applications, including quantum technologies and materials science.