Saturation of electron dephasing in three-dimensional polycrystalline disordered metals

Abstract

We have systematically investigated the low-temperature electron dephasing times tau (phi) in more than 40 three-dimensional polycrystalline impure metals with distinct material characteristics. In all cases, a saturation of the dephasing time is observed below about a (few) degree(s) Kelvin, depending on samples. The value of the saturated dephasing time tau (0) [= tau (phi)(T --> 0 K)] falls basically in the range 0.005 to 0.5 ns for all samples. Particularly, we find that so scales with the electron diffusion constant D as tau (0) similar to D-alpha, with alpha close to or slightly larger than 1, for over two decades of D from about 0.1 to 10 cm(2) s(-1). Our observation implies an essentially constant saturated dephasing length of rootD tau (0) similar to 1000 Angstrom in three-dimensional polycrystalline disordered metals. A complete theoretical explanation is not yet available.