An investigation was made of the structure, energetics, and effects of stacking faults in MgB2 by means of first-principles density-functional calculations. Two structurally different stacking faults were determined (figures 3 to 6) with displacements of R = [0 1/2 0] (type-A) and [2/3, 1/3 0] (type-B), and the formation energies were calculated to be 956 and 932erg/nm2, respectively. Significant expansions were found at both faults. The partial density of states showed that the B atoms in these stacking faults exhibited large reductions in the density of states around the Fermi energy. However, due to their low density, these stacking faults were not expected to cause a significant decrease in the transition temperature.

Structures, Energetics and Effects of Stacking Faults in MgB2. Y.Yan, M.M.Al-Jassim: Physical Review B, 2002, 66[5], 052502 (4pp)