Formation energy and interaction of point defects in two-dimensional colloidal crystals

Autor(es)

DaSilva‚ LC ; Candido‚ L. ; Costa‚ L.F. ; Oliveira Jr‚ O.N.

• Tipo de documento: Artigo Científico
• Fonte: Physical Review B; v. 76, n. 3, p. 035441, 2007.

Resumo

The manipulation of individual colloidal particles using optical tweezers has allowed vacancies to be created in two-dimensional (2D) colloidal crystals, with unprecedented possibility of real-time monitoring the dynamics of such defects [Nature (London) 413, 147 (2001)]. In this paper, we employ molecular dynamics simulations to calculate the formation energy of single defects and the binding energy between pairs of defects in a 2D colloidal crystal. In the light of our results, experimental observations of vacancies could be explained and then compared to simulation results for the interstitial defects. We see a remarkable similarity between our results for a 2D colloidal crystal and the 2D Wigner crystal [Phys. Rev. Lett. 86, 492 (2001)]. The results show that the formation energy to create a single interstitial is 12%-28% lower than that of the vacancy. Because the pair binding energies of the defects are strongly attractive for short distances, the ground state should correspond to bound pairs with the interstitial bound pairs being the most probable. (AU)

• Processo FAPESP: 05/00587-5 - Modelagem por redes (grafos) e técnicas de reconhecimento de padrões: estrutura, dinâmica e aplicações
• Beneficiário: Roberto Marcondes Cesar Junior
• Modalidade de apoio: Auxílio à Pesquisa - Temático