Lechner, Christian and Rössler, Ulrich (2004) Extension of the Semiconductor Bloch Equations for Spin Dynnamics. In: Menéndez, José and Van de Walle, Chris G., (eds.) Physics of semiconductors Semiconductors: 27th International Conference on the Physics of Semiconductors; ICPS-27; Flagstaff, Arizona, 26 - 30 July 2004. AIP conference proceedings, 772. American Institute of Physics Publishing, New York. ISBN 0-7354-0257-4.
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The dynamics of the spin of carriers has attracted a lot of attention in the last few years especially with respect to spintronics and quantum computation. Spin dephasing and relaxation times are usually studied using time-resolved spectroscopy with circularly polarized light . Carrier dynamics in semiconductors and semiconductor heterostructures under excitation with light are usually described within the concept of the Semiconductor Bloch Equations (SBE), which was originally designed for a two-level system and a scalar electric field . It includes electron-electron interaction but does not account for the degrees of freedom of the carrier spin and the polarization of the light field. In order to overcome these limitations, we use an extension of the SBE to a four-level system, including spin-split levels for holes and electrons and the vector character of the light field . Scattering processes due to carrier-carrier and carrier-phonon interaction are taken into account, which in combination with spin-orbit interaction become spin-sensitive. By evaluating the Liouville equation we obtain a set of equations of motion (EOM) of the density matrix, which due to spin-dependent many-particle interactions exhibits a hierarchical structure and needs to be properly truncated for further treatment. In contrast to the Hartree-Fock truncation, which leads to coherent SBE, we include incoherent processes in lowest order in the entries of the density matrix. For the diagonal entries these first order corrections of the EOM can be rewritten as Boltzmann-like scattering contributions. In conclusion, by extending the SBE to a four-level system and by including energy dissipating processes we have found an access to describe spin relaxation and spin dephasing on a microscopical level.
|Item Type:||Book Section|
|Institutions:||Physics > Institute of Theroretical Physics > Retired Professors > Group Ulrich Rössler|
|Projects:||Forschergruppe Ferromagnet-Halbleiter Nanostrukturen|
|Subjects:||500 Science > 530 Physics|
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Deposited On:||20 Mar 2007|
|Last Modified:||05 Aug 2009 13:29|