Short-range correlations in binary alloys: Spin model approach to AgcAu1−c and AgcPd1−c

Abstract

Short-range correlations in Ag–Au and Ag–Pd alloys are investigated by analyzing the ab initio total energy of face centered cubic (fcc) based random AgcAu1−c and AgcPd1−c. Since the information on the atomic interactions is incorporated in the energetics of alloys it is possible with a suitable model, Bethe–Peierls–Weiss model is used in the present work, to invert the problem, i.e. to obtain information on the short-range correlation from the total energy of a random system. As an example we demonstrate how site correlations can be extracted from random alloy data. Bethe–Peierls–Weiss model predicts negative (positive) first neighbor correlator for substitutional fcc Ag–Au and (Ag–Pd) alloys at low temperature which can be related to the optimal structures of Ag0.5Au0.5 (and Ag0.5Pd0.5).