I What is the relation between scattering and mobility in solid state physics?

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    Scattering Time
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Scattering time is a crucial concept in solid state physics, referring to the duration a charge carrier is accelerated by an electric field before colliding with an obstacle that alters its direction or energy. This time directly influences the mobility of carriers, which is defined by their drift velocity. Key sources of scattering in semiconductors include ionized impurity scattering and acoustic phonon scattering, with other factors like neutral impurities and surface defects also playing a role. Understanding these relationships is essential for grasping carrier dynamics in solid state materials. The discussion highlights the complexity and sometimes vague definitions present in solid state physics literature.
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I came across the term scattering time in Simon's "The Oxford Solid State Physics".

Apparently it's supposed to be obvious because I can't find a definition anywhere but what is it? Why is so much stuff left undefined in solid state physics?
 
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This wiki article discusses it as well as other solid state terminology:

https://en.wikipedia.org/wiki/Elect...determining drift,its direction and/or energy.

Relation between scattering and mobility[edit]​

Recall that by definition, mobility is dependent on the drift velocity. The main factor determining drift velocity (other than effective mass) is scattering time, i.e. how long the carrier is ballistically accelerated by the electric field until it scatters (collides) with something that changes its direction and/or energy. The most important sources of scattering in typical semiconductor materials, discussed below, are ionized impurity scattering and acoustic phonon scattering (also called lattice scattering). In some cases other sources of scattering may be important, such as neutral impurity scattering, optical phonon scattering, surface scattering, and defect scattering.[12]
 
From the BCS theory of superconductivity is well known that the superfluid density smoothly decreases with increasing temperature. Annihilated superfluid carriers become normal and lose their momenta on lattice atoms. So if we induce a persistent supercurrent in a ring below Tc and after that slowly increase the temperature, we must observe a decrease in the actual supercurrent, because the density of electron pairs and total supercurrent momentum decrease. However, this supercurrent...