Dingle temperatures and Fermi surface changes in dilute substitutional Cu alloys. II. Lattice distortion effects

For pt.I see ibid., vol.73, p.839 (1983). Lattice distortion (LD) effects on Dingle temperatures x* and cross-sectional area changes delta A are studied in dilute Cu alloys. An impurity cluster formalism is applied to a cluster consisting of 13 atoms embedded in Cu. First model calculations are reported for a pure Cu crystal with artificial relaxation. The results mainly lead to the conclusion that summing up to lmax=3 is necessary if LD is accounted for. Applying the theory to Si, P, Z, Al and Ge as impurities in Cu it is found that the effect of LD on x* and delta A depends linearly on the shift of the first shell around the impurity. Further it appears that x* is much more sensitive to LD than is delta A. Depending on the orbit the corrections to x* from LD and charge transfer may be of nearly equal importance. Because these corrections sum up rather independently, neglecting both effects may cause errors up to an order of 20%.