ABSTRACT
In numerous experiments involving electrons, the ability to manipulate the spin of the electron gives unique additional information. For many years, however, such experiments were extraordinarily rare because of the absence of a good source of spin-polarized electrons. When GaAs Spin-Polarized Electron Source appeared in print, a large number of proposed measurements were standing by, awaiting an improved source of spin-polarized electrons. The principle of the GaAs polarized electron source relies on the photoexcitation of spin-polarized electrons in a solid and their escape into vacuum. The two interactions, the spin-orbit interaction and the exchange interaction, that give rise to spin-dependent electron scattering from surfaces were investigated at NBS and given as examples of applications in the paper GaAs Spin-Polarized Electron Source. An especially important application of spin-polarized electrons is illustrated by a SEMPA investigation that took place in the early nineties.
