Lecture on semiclassical theory

On Tuesday I gave a lecture about the semiclassical theory, completing the simplification of the regular Boltzmann equation presented in materials physics books to that in the diffusive limit (diffusion equation for distribution function, written separately for each energy), and finally to the quasiequilibrium limit, where it is enough to write equations for position dependent potential and temperature. I think the message went through quite well, I managed to avoid excessive derivations (which IMHO should not be given too much in the lecture, because they tend to confuse the students from the physics), and I got some good questions.

The diffusive limit can be represented using the circuit theory, and especially in the quasiequilibrium limit it is a convenient tool. I am not sure if this becomes very clear from my book, though, so this should be improved a bit. Anyway, I used its ideas to talk about some basic phenomena in spintronics, like the spin accumulation and the giant magnetoresistance. Let’s see if the students understood it – there were two exercise problems on them.

Today I will talk about scattering theory, which I already started in Tuesday’s lecture.