PEIERLS BARRIERS AND STRESSES FOR EDGE DISLOCATIONS IN PD AND AL CALCULATED FROM FIRST PRINCIPLES

We report generalized stacking fault (GSF) curves along the [121] and [110] directions for Pd and Al, calculated from first principles. The GSF curves are applied in the classic PN model to calculate Peierls ba rriers and stresses for the Shockley partials and the unsplit edge dis locations in Pd and Al. The obtained stresses using relaxed GSF curves agree well with experiments. The numerical results are also compared with a recently derived analytical expression for the Peierls stress. The GSF curves have been calculated with a pseudopotential implementat ion of density functional theory. The accuracy of the method have been tested by calculating values for various stacking fault energies of A l, Ni, Cu, Ag, and Pd which favorably compare with other theoretical a nd experimental values. [S0163-1829(98)02229-2].