Interaction energy and point-defect configurations in two-dimensional colloidal crystals

We investigate the interaction energy between two defects with different topological configurations in two-dimensional colloidal crystal using Brownian dynamics simulations with Yukawa pair potential. We observed that repulsive interactions exist for three vacancy-vacancy (approximately 15% probability) and four interstitial-interstitial (approximately 7% probability) configurations. Furthermore, considering the occurrence probability of the configuration of defect pairs, it is observed that the average binding energy between two defects is still attractive for both interstitials and vacancies. Based on the displacement of point defects, we qualitatively analyze the ranking of the interaction energies for different pair configurations, which is consistent with the simulation results.