Surface effects on stacking fault and twin formation in fcc nanofilms: A first-principles study

The free surface effects on stacking fault and twin formation in fcc metals (Al, Cu, and Ni) were examined by first-principles calculations based on density functional theory (DFT). It is found that the generalized planar fault (GPF) energies of Ni are much larger than bulk Ni with respect to Al and Cu. The discrepancy is attributed to the localized relaxation of Ni nanofilm to accommodate the large expansion of the interplanar separation induced at the fault plane. The localized relaxation can be coupled to the electronic structure of Ni nanofilms.

► The propensity of stacking fault and twin formation is examined in bulk and nanofilms of fcc metals.
► The GPF energies of Ni nanofilm are much larger than bulk Ni with respect to Al and Cu.
► It is discovered that interlayer relaxation is an important factor affecting the GPF energies.