Residual resistivity
= Residual resistivity
{title2=$\rho_0$}
The <residual resistivity> is the low-<temperature> <electrical resistivity> remaining in a normal <metal> when thermally excited scattering becomes negligible. Static disorder, impurities and boundaries can relax carrier <momentum> without requiring a thermal population of <phonons>. Its value depends on sample purity and structure; a superconducting transition is a different phenomenon.