Electronic structure of random binary alloys : an augmented space formulation in reciprocal space

TL;DR

This paper introduces a reciprocal space formulation of the augmented space recursion method for calculating electronic structures of random alloys, improving accuracy by exactly accounting for real space contributions.

Contribution

The authors develop a reciprocal space approach to the augmented space recursion, enhancing the precision of electronic structure calculations for disordered alloys.

Findings

More accurate spectral functions and band structures for Ni50Pt50 alloy.

Effective Brillouin zone integration for density of states.

Foundation for future optical conductivity calculations in random systems.

Abstract

We present here a reciprocal space formulation of the Augmented space recursion (ASR) which uses the lattice translation symmetry in the full augmented space to produce configuration averaged quantities, such as spectral functions and complex band structures. Since the real space part is taken into account {\sl exactly} and there is no truncation of this in the recursion, the results are more accurate than recursions in real space. We have also described the Brillouin zone integration procedure to obtain the configuration averaged density of states. We apply the technique to Ni$_{50}$Pt$_{50}$ alloy in conjunction with the tight-binding linearized muffin-tin orbital basis. These developments in the theoretical basis were necessitated by our future application to obtain optical conductivity in random systems.