Kinetic Theory of Spin Coherence of Electrons in Semiconductors

We investigate the spin precession and dephasing of electrons in semiconductors, using the kinetic Bloch equations for a four-spin-band model. Various scatterings, such as carrier–carrier, carrier–phonon, and carrier–impurity scatterings are taken into account. Their contributions to the evolution of carrier distribution, optical coherence, and more importantly, spin coherence in undoped semiconductor quantum wells and in n-type bulk semiconductors are considered. We highlight the importance of the kinetic theory approach by comparing our results with those from Fermi's golden rule. Furthermore, a new spin dephasing mechanism is proposed, that is, spin dephasing due to spin conserving scatterings in the presence of inhomogeneous broadening.