Basal-plane stacking faults in wurtzite AlN, GaN, and InN are studied using density-functionalpseudopotential calculations. The formation energies follow the trend exhibited for the zinc-blende/wurtzite energy differences in the bulk materials, namely, lowest energy for GaN and highest for AlN. Type-I stacking faults have the lowest energy, followed by type-II stacking faults, and finally extri...

A density functional theory–phase field dislocation dynamics model is used to study stress-induced emission of defects from grain boundaries in nanoscale face-centered cubic (fcc) crystals under ambient conditions. The propensity for stable stacking fault formation and the maximum grain size DSF below which a stacking fault is stable are found to scale inversely with the normalized intrinsic st...

Impressive opto-electronic devices and transistors have recently been fabricated from GaAs nanopillars grown by catalyst-free selective-area epitaxy, but this growth technique has always resulted in high densities of stacking faults. A stacking fault occurs when atoms on the growing (111) surface occupy the sites of a hexagonal-close-pack (hcp) lattice instead of the normal face-centered-cubic ...

To understand the effects of alloying elements on the creep rate of Ni-base superalloys, factors entering into a secondary creep rate are calculated via first-principles calculations based on density functional theory for 26 Ni31X systems where X = Al, Co, Cr, Cu, Fe, Hf, Ir, Mn, Mo, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ta, Tc, Ti, V, W, Y, Zr, and Zn. They are volume, elastic properties, stacki...

When load is applied to fcc nanograins, leading partial dislocations nucleate at grain boundary steps and propagate into the grain, leaving stacking faults behind. The extent to which these faults expand before a trailing partial is emitted generally does not equal the equilibrium separation distance of the corresponding full dislocation. Here we use a density functional theory – phase field di...

The diffusion of an interstitial Si atom along an edge dislocation in Al is studied by using a quantummechanics/molecular-mechanics coupling method. It is found that the diffusing Si atom follows approximately a sinusoidal trajectory. The diffusion energy barrier along the partial dislocation core is in excellent agreement with the experimental value. We predict that the stacking fault ribbon c...

The equilibrium of dissociated dislocations is discussed in terms of intrinsic material properties such as the ideal stacking fault energy (ideal SFE) and the stacking fault (SF) strain. The ideal SFE is de® ned as the energy per unit area of an in® nitely extendedSF in an ideal in® nite crystal. The e€ ective SFE is de® ned as the energy per unit area of a terminated SF. The terminated SF is a...