A Finite-Size Supercell Correction Scheme for Charged Defects in   One-Dimensional Systems
  We propose a new finite-size correction scheme for the formation energy of charged defects and impurities in one-dimensional systems within density functional theory. The energy correction in a supercell geometry is obtained by solving the Poisson equation in a continuum model which is described by an anistrotropic permittivity tensor, with the defect charge distribution derived from first-principles calculations. We implement our scheme to study impurities and dangling bonds in silicon nanowires and demonstrate that the formation energy of charged defects rapidly converges with the supercell size. 
Sunghyun Kim, Ji-Sang Park and K. J. Chang
cond-mat.mtrl-sci