title: Single and paired point defects in a 2D Wigner crystal.
abstract: Using the path-integral Monte Carlo method, we calculate the energy to form single and pair vacancies and interstitials in a two-dimensional Wigner crystal of electrons. We confirm that the lowest energy point defects of a 2D electron Wigner crystal are interstitials, with a creation energy roughly 2/3 that of a vacancy. The formation energy of the defects goes to zero at melting, suggesting that point defects may be the melting mechanism and that the melting could be a continuous transition. In addition, we find that the interaction between defects is strongly attractive, so that most defects will exist as bound pairs.
authors.affiliation: Loomis Laboratory of Physics and NCSA, University of Illinois at Urbana-Champaign, 1100 West Green Street, Urbana, Illinois 61801-3080, USA.
authors.forename: L
authors.initials: L
authors.lastname: Cândido
authors.forename: P
authors.initials: P
authors.lastname: Phillips
authors.forename: D M
authors.initials: DM
authors.lastname: Ceperley