First-Principles Investigation of Thermoelectric Properties in Cu-Ni Alloys

We present a first-principles study of the thermoelectric properties of Cu_1-xNi_x alloys, focusing on the Seebeck coefficient and the dimensionless figure of merit (zT). Employing the Korringa-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA) as implemented in the SPR-KKR package [1], alongside electronic transport calculations for random alloys via the Kubo-Greenwood formula implemented in the MuST package [2], we investigate a wide range of compositions and temperatures. Our calculations incorporate finite temperature effects, including atomic displacements and magnetic fluctuations, through the alloy analogy model (AAM) [3]. The analysis of the density of states (DOS) reveals significant restructuring of electronic states near the Fermi level with varying Ni concentration, indicating band convergence and increased electronic asymmetry. These DOS modifications facilitate an enhanced Seebeck coefficient, with peak values at specific compositions. The figure of merit follows a similar trend, benefiting from the optimized Seebeck coefficient and elevated electrical conductivity due to reduced carrier scattering rates. These findings validate the efficacy of first-principles methods in modeling thermoelectric behavior in disordered magnetic alloys.