First-Principles Calculations of Second-Order Elastic Constants and Generalized-Stacking-Fault Energy for GaAs

The second-order elastic constants and generalized-stacking-fault energy surfaces for semiconductors GaAs have been predicted by using the first-principles calculations. The calculations employ the density functional theory within local-density-approximation method. The lattice constants of GaAs is 5.626 angstrom, which agree well with the experimental data 5.65 angstrom and theoretical values 5.6045 angstrom(LDA). The SOECs agree well with the experimental data and theoretical values. The generalized-stacking-fault energy curves along <110>{111} direction of the shuffle set in GaAs have been calculated. Based on the Fourier series, the fitted generalized-stacking-fault energy surfaces have been obtained. The dislocation width and Peierls stress for shuffle 60 degrees dislocation in GaAs have been calculated by the improved Peierls-Nabarro theory in which non-relaxed and relaxed calculations have been taken into account. The calculated dislocation width is narrow(about 0.83b), and the peierls stress is about 0.45 similar to 0.54GPa.