Resistivity in Dilute Cu-3d Alloys Governed by Disorder-Induced Band Broadening

Abstract

The mechanism governing the resistivity in dilute Cu-3d transition-metal alloys at ambient temperature -- the regime relevant to most practical applications and distinct from the low-temperature, Kondo-screened regime addressed by earlier theoretical work -- is investigated using first-principles calculations based on the Korringa--Kohn--Rostoker coherent potential approximation combined with the Kubo--Greenwood formalism. The paramagnetic state is described within the disordered local moment (DLM) framework, corresponding to a local-moment paramagnet rather than a Pauli paramagnet. We show that the experimentally observed resistivity trends are reproduced only within the DLM description, while nonmagnetic and ferromagnetic states fail to capture the correct element dependence. Contrary to conventional interpretations based on the density of states at the Fermi level, the resistivity exhibits a strong correlation with the full width at half maximum (FWHM) of the Bloch spectral function (BSF) on the Fermi surface. This correlation reflects the disorder-induced lifetime broadening of electronic states, directly related to the scattering rate that governs electrical resistivity. A common power-law scaling between resistivity and BSF broadening is identified across different magnetic states. These results demonstrate that the resistivity is governed by disorder-induced band broadening in momentum space rather than by local density-of-states effects, providing a unified microscopic interpretation of the breakdown of Linde's rule in Cu-based alloys.