Atomicstructureofdislocationkinksinsilicon-Department.PDFVIP

PHYSICAL REVIEW B VOLUME 57, NUMBER 17 1 MAY 1998-I Atomic structure of dislocation kinks in silicon R. W. Nunes Complex System Theory Branch, Naval Research Laboratory, Washington, DC 20375-53459 and Computational Sciences and Informatics, George Mason University, Fairfax, Virginia 22030 J. Bennetto and David Vanderbilt Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855-0849 Received 16 July 1997; revised manuscript received 15 October 1997 We investigate the physics of the core reconstruction and associated structural excitations reconstruction defects and kinks of dislocations in silicon, using a linear-scaling density-matrix technique. The two predomi- nant dislocations the 90° and 30° partials are examined, focusing for the 90° case on the single-period core reconstruction. In both cases, we observe strongly reconstructed bonds at the dislocation cores, as suggested in previous studies. As a consequence, relatively low formation energies and high migration barriers are generally associated with reconstructed dangling-bond-free kinks. Complexes formed of a kink plus a reconstruction defect are found to be strongly bound in the 30° partial, while the opposite is true in the case of 90° partial, where such complexes are found to be only marginally stable at zero temperature with very low dissociation barriers. For the 30° partial, our calculated formation energies a