Structure and Energetics of Stacking Faults

The four-body term is an application of exactly the ideas introduced in section 4.5.3 and culminating in eqn (4.95). Fig. 9.32 shows the relative contributions of different atoms in the faulted region to the overall fault energy. In particular, for a series of different metals the overall contribution to the stacking fault energy is decomposed layer by layer and each such contribution is itself decomposed into the relative contributions of the pair and four-body terms. 

The parameters 7 are the effective Ising parameters that are determined from 

To compute the stacking fault energy, we must evaluate AE = EfauUediN layers) — EperfectiN layers). For the extrinsic case given above only four layers (i.e. 11—1—1 have contributions that are different from the perfect crystal contribu- 

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