Spin and Spin-Orbit Coupling Sample Clauses

Spin and Spin-Orbit Coupling. It was after a detailed study of spectroscopic data that Xxxxxxxxx and Xxxxxxxx came to suggest that the electron has spin, an intrinsic angular 3Ehrenfest’s contribution, allowing his students to go ahead with a wild idea with the words “you are both young enough to be able to afford a stupidity”, was crucial. About the same time, Xxxxx Xxxxxx had similar ideas, but the response of his supervisor, Xxxxxxxx Xxxxx, “it is indeed very clever but of course has nothing to do with reality”, was in stark contrast to Ehrenfest’s. 4Strictly speaking, xxx Xxxxxxxxx time does not come directly from Ehrenfest himself. Xxx Xxxxxxxxx time τE is the time it takes a wavepacket to spread to a size on the order of the system size. For times smaller then τE the center of the wavepacket and its group velocity satisfy Ehrenfest’s theorem, thus the name. momentum that gives arise to a magnetic moment. Most physicists first acquaintance with spin, however, is through a recount of xxx Xxxxx-Xxxxxxx experiment [2]. Building on this familiarity, we will begin our discussion by using a combination of the results of the experiment and classical argu- ments to deduce the presence of the spin and a coupling of this spin to the orbital motion. The same results are then obtained more rigorously from the nonrelativistic limit of the Dirac equation. In turn, this leads us to an analysis of the rotation properties of spin and the accompanying Berry phase. We demonstrate the importance of this phase by considering its role in weak (anti) localization. To complete this section, we sketch how the spin-orbit coupling in semiconductors gives rise to the familiar Rashba and Dresselhaus terms.