From: David Vanderbilt <dhv@physics.rutgers.edu> Date: Tue, 8 Aug 2000 21:02:59 GMT (3kb)
Authors:
R.W. Nunes (Departamento de Fisica, Universidade Federal de Minas Gerais, Brazil),
David Vanderbilt (Department of Physics and Astronomy, Rutgers University)
Comments: 1 page. Submitted to Comments section of PRL. Also available at
this http URL
Subj-class: Materials Science
In a recent Letter [N. Lehto and S. Oberg, Phys. Rev. Lett. 80, 5568 (1998)], Lehto and Oberg investigated the effects of strain fields on the core structure of the 90-degree partial dislocation in silicon, especially the influence of the choice of supercell periodic boundary conditions in theoretical simulations. We show that their results for the relative stability between the two structures are in disagreement with cell-size converged tight-binding total energy (TBTE) calculations, which suggest the DP core to be more stable, regardless of the choice of boundary condition. Moreover, we argue that this disagreement is due to their use of a Keating potential.