4 research outputs found
New Physics of the Partial Dislocation in Silicon Revealed through {\em Ab Initio} Calculation
Based on {\em ab initio} calculation, we propose a new structure for the
fundamental excitation of the reconstructed 30 partial dislocation in
silicon. This soliton has a rare structure involving a five-fold coordinated
atom near the dislocation core. The unique electronic structure of this defect
is consistent with the electron spin resonance signature of the hitherto
enigmatic thermally stable R center of plastically deformed silicon. We present
the first {\em ab initio} determination of the free energy of the soliton,
which is also in agreement with the experimental observation. This
identification suggests the possibility of an experimental determination of the
density of solitons, a key defect in understanding the plastic flow of the
material.Comment: 6 pages, 5 postscript figure
Robust ab initio calculation of condensed matter: transparent convergence through semicardinal multiresolution analysis
We present the first wavelet-based all-electron density-functional
calculations to include gradient corrections and the first in a solid. Direct
comparison shows this approach to be unique in providing systematic
``transparent'' convergence, convergence with a priori prediction of errors, to
beyond chemical (millihartree) accuracy. The method is ideal for exploration of
materials under novel conditions where there is little experience with how
traditional methods perform and for the development and use of chemically
accurate density functionals, which demand reliable access to such precision.Comment: 4 pages, 3 figures, 4 tables. Submitted to Phys. Rev. Lett. (updated
to include GGA