Methodological Framework for Investigating Thermoelectric Transport in Cu-Ni Alloys Using First-Principles Calculations

We present the methodological approach for studying the thermoelectric properties of random alloys through first-principles electronic structure and transport simulations. Using the Korringa-Kohn-Rostoker (KKR) method within the Coherent Potential Approximation (CPA) framework, as implemented in the SPR-KKR package, and the MuST software, we examine various alloy compositions and temperature regimes.

Electronic structure is determined through self-consistent KKR-CPA calculations, followed by transport property evaluations. We compute electrical conductivity using the Kubo-Bastin formalism in SPR-KKR and the Kubo-Greenwood formalism in MuST, from which the Seebeck coefficient and figure of merit (zT) are derived.

In this study, we focus on copper-nickel (Cu₁₋ₓNiₓ) alloys. Finite temperature effects, including atomic displacements and magnetic fluctuations, are modeled via the alloy analogy model (AAM). Results show a non-linear Seebeck coefficient variation with Ni concentration, linked to electronic states near the Fermi level. Composition-dependent trends in zT are observed, with finite temperature disorder improving agreement with experimental data. This framework is applicable to other metallic alloy systems for thermoelectric studies.