  We extended and corrected Mott's two-band model for the
composition-dependence of thermal and electrical conductivity in binary metal
alloys based on high-throughput time-domain thermoreflectance (TDTR)
measurements on diffusion multiples and scatterer-density calculations from
first principles. Examining PdAg, PtRh, AuAg, AuCu, PdCu, PdPt, and NiRh binary
alloys, we found that the nature of the two dominant scatterer-bands considered
in the Mott model changes with the alloys, and should be interpreted as a
combination of the dominant element-specific s- and/or d-orbitals. Using
calculated orbital and element-resolved density-of-states values calculated
with density functional theory as input, we determined the correct orbital mix
that dominates electron scattering for all examined alloys and find excellent
agreement between fitted models and experiments. The proposed description of
the composition dependence of the resistivity can be readily implemented into
the CALPHAD framework.
