Electron mean free path in elemental metals

Abstract

The electron mean free path λ and carrier relaxation time τ of the twenty most conductive elemental metals are determined by numerical integration over the Fermi surface obtained from first-principles, using constant λ or τ approximations and wave-vector dependent Fermi velocities vf (k). The average vf deviates considerably from the free-electron prediction, even for elements with spherical Fermi surfaces including Cu (29% deviation). The calculated product of the bulk resistivity times λ indicates that, in the limit of narrow wires, Rh, Ir, and Ni are 2.1, 1.8, and 1.6 times more conductive than Cu, while various metals including Mo, Co, and Ru approximately match the Cu resistivity, suggesting that these metals are promising candidates to replace Cu for narrow interconnect lines.