The basal twin of α-Cr2O3 nanocondensates: occurrence and first-principles calculations

Abstract

The α-Cr₂O₃ nanocondensates prepared by pulsed laser ablation were identified by transmission electron microscopy to have a coherent basal twin boundary and well-developed (0001) and (10) surfaces. The cause of such a basal twin with a Burgers vector = 1/3[10] can be rationalized by the (0001)-specific rotation/coalescence of the crystalline nanocondensates to form a 2-D coincidence site lattice with an excess energy of 13 eV nm⁻² according to first-principles density functional calculations. The unification/twinning bifurcation of the sesquioxide atom clusters that were previously coalesced can be explained by the critical particle size and the temperature for anchorage release at the interface.