Ab Initio Calculations Of Structural Properties Research Articles

Impact of electronic structure calculations on the study of diffusion in metals

Developments in electronic structure calculations and computer performances have made it possible to perform ab-initio calculations of structural properties of materials, like defect parameters in transition metals. The values of vacancy formation and migration enthalpies calculated in this context agree with experimental data within less than 10% . Reliable self-diffusion coefficients for the vacancy mechanism can be deduced. This approach sheds new light on the so-called self-diffusion anomaly in body centred cubic metals.

Structure of 6H–SiC(0001) Surfaces from AB-Initio Calculations

We report the results of ab-initio calculations of structural properties of hexagonal 6H–SiC(0001) surfaces. The calculations have been carried out self-consistently within local density approximation employing supercell geometries, smooth norm-conserving pseudopotentials in separable form and Gaussian orbital basis sets. We have investigated several structural models for adatom-induced [Formula: see text] reconstructions with adsorbed Si or C adatoms or trimers residing in threefold-symmetric T 4 or H 3 positions above Si- or C-terminated substrate surfaces, respectively. In the case of the Si-terminated substrate surface our results favor Si adatoms in T 4 sites as optimal configuration in very good agreement with experimental data. For the C-terminated substrate surface our results indicate that none of the investigated [Formula: see text] adatom or trimer configurations is the optimal surface structure.