Theory of interface energies

Abstract

We have developed a practical scheme for the calculation of interface energies. It combines the theory of generalized Wannier functions, the generalized recursion method for calculating local densities of states and electronic density, and the local-density-functional theory. As a first application of this method we are calculating the stacking-fault energy of nickel using tight-binding-type Wannier functions for the $d$ electrons and ignoring the effect of the $s$ electrons. The $d$-band degeneracy is fully taken into account. The method also allows one to handle charge-transfer effects: a stacking-fault perturbation potential is included and calculated self-consistently. Comparison is made between the moment scheme, the non-self-consistent scheme, and the self-consistent scheme. Earlier moment calculations, up to the fourth moment, lead to stacking-fault energies which are a factor of 3 smaller than our more complete calculations. We also find that the self-consistent refinement affects the stacking-fault energy very little. Our best theoretical result is still much smaller, by a factor of about 3-7, than the (rather uncertain) experimental energy.