An augmented space approach to the study of random ternary alloys: I. Electronic structure with uncorrelated disorder and short ranged order.

We present here a generalized augmented space recursive technique which includes the effects of diagonal and environmental disorder explicitly: an analytic, lattice translational invariant, multiple scattering theory for the study of short range ordering in random ternary alloys. Our generalized augmented space formalism includes atomic correlations over a finite cluster including short range order (SRO). We propose the augmented space recursion (ASR), a computationally fast and accurate technique which incorporates configuration fluctuations over a large local environment. We apply the formalism to a tight-binding linear muffin-tin orbital (LMTO) study of stainless steel Fe(80-x)Ni(x)Cr(20) (x = 14 and 17). We have demonstrated the effects of short range ordering by calculating the configuration averaged density of states with and without SRO and with different kinds of cluster environment embedded in an averaged medium.