Theory of electronic transport in random alloys with short-range order: Korringa-Kohn-Rostoker nonlocal coherent potential approximation

We present an ab initio formalism for the calculation of transport properties in compositionally disordered systems within the framework of the Korringa-Kohn-Rostoker nonlocal coherent potential approximation. Our formalism is based on the single-particle Kubo-Greenwood linear response and provides a natural means of incorporating the effects of short-range order upon the transport properties. We demonstrate the efficacy of the formalism by examining the effects of short-range order and clustering upon the transport properties of disordered AgPd and CuZn alloys.

Figure 1

(Color online) The resistivity of randomly disordered alloys ${\mathrm{Ag}}_c{\mathrm{Pd}}_{1-c}$ alloys as a function of concentration $c$. The full lines are the NLCPA results [pink (green) lines with squares (diamonds) show those without (with) vertex corrections]. The dashed curves show the CPA results [long dashes (dots)—without (with) vertex corrections]. The experimental results of Guenault (Ref. 58) are shown for comparison (full blue lines with filled circles).

Figure 2

(Color online) The resistivity of ${\mathrm{Cu}}_c{\mathrm{Zn}}_{1-c}$ alloys as a function of concentration $c$. The full (red) line with crosses shows the calculations when no SRO is included. [These are nearly indistinguishable from the CPA results (green line).] The (green) line with asterisks shows the NLCPA results when SRO is included and the square boxes (light blue line) show results when short-ranged clustering is included. Results are also shown where the vertex corrections have not been included: full (yellow) line with plus signs—NLCPA results for no SRO, (the dashed line shows the CPA results); lines with diamonds—NLCPA results including SRO; and lines with triangles—NLCPA results including short-ranged clustering.

Figure 3

(Color online) The resistivity of ${\mathrm{Ag}}_c{\mathrm{Pd}}_{1-c}$ alloys as a function of concentration $c$. The full (green) line with diamonds shows the calculations when no SRO is included. The (red) line with triangles shows those when SRO is included. Vertex corrections are included in both plots. The experimental data (Ref. 58) are also shown (blue line with filled circles).