Interaction Energy And Point-defect Configurations In Two-dimensional Colloidal Crystals

The properties of materials are significantly affected by the types and concentrations of defects. Even in the limit of zero temperature, delocalized defects are hypothesized to be present in crystalline solid. The role of point defects on the melting of2D systems has also been studied in detail. The interaction between dislocations plays an important role in the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) theory. The unbinding of dis-location pairs indicates the transition from the solid phase to the hexatic phase, and the unbinding of disclinations signals the transition from the hexatic phase to the liquid phase.Controllable colloidal particles are sufficiently large to be observed us-ing microscopy techniques, and they provide a good model for condensed-matter physics investigations.Based on the similarity of atoms and colloid partices, we investegate the interaction between point defects, our result shows that:except the attractive interaction energy which have been showen by previous researchers, there are repulsive interaction energy between both for two intertials and two vacancies. In fact, the probablity of the attractive interaction energy for vacancies are15%,7%for intertials, based on the displacement of the defects, we explained the sequence of the interaction energy, greater displacement corresponding to greater interaction energy no matter attractive or repulsive, parallel displacement can diminish the inter-action energy, while the crossed displacement would raise the interaction energy.Our results goes further than previous researchers, because, though there exist repulsive interaction energy, in statistic, it is attractive.