arXiv subjects

Torkel D. Engeness

Publications and source records attributed to Torkel D. Engeness.

2 recordsLinked to original sources

arXiv2002

Multiresolution analysis for efficient, high precision all-electron density-functional calculations

Multiresolution analysis of electronic structure affords the opportunity to capture the full physics of atomic cores in a systematically improvable manner. Applying new techniques, we demonstrate for the first time that multiresolution analysis of all-electron calculations within density-functional theory can be carried out to high precision with a computational effort comparable to that of the corresponding plane-wave pseudopotential calculation, which neither captures the full core physics nor is systematically improvable. With this approach, we present calculations of paramagnetic core-level shifts where local density-functional theory is the sole uncontrolled approximation.

cond-mat↗

arXiv2000

New Physics of the $30^\circ$ 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$^\circ$ 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.

cond-mat.mtrl-sci↗