dc conductivity of strong and weak electron spin-orbit scattering materials near the metal-insulator transition

A detailed comparison of two disordered alloys, Geₓ{Au}_{1{{-}}x}$ and ${B}ₓCu_1-x, is carried out near their metal-insulator transition in zero magnetic field. Geₓ{Au}_{1{{-}}x}$, a high-Z material, has been shown to exhibit strong spin-orbit effects in a magnetic field, while ${B}ₓCu_1-x, a low-Z material, has been shown to exhibit weak spin-orbit effects. Both materials have similar temperature-dependent dc conductivity behavior in zero field and approximately linear mobility edges.