Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 3: Spintronik I

HL 3.1: Talk

Friday, March 4, 2005, 10:45–11:00, TU P164

A microscopic approach to semiconductor spin dynamics — •Christian Lechner and Ulrich Rössler — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany

In recent years the spin degree-of-freedom of carriers in semiconductors and semiconductor heterostructures has become essential for the development of spintronic devices. For their realization the understanding of spin relaxation and spin dephasing is of central importance. The corresponding relaxation times have so far mostly been described by phenomenological models.

Here we present a microscopic theory of the spin dynamics with emphasis on spin-relaxation and -dephasing due to electron-phonon interaction. We use the density matrix approach known from the description of ultrafast carrier dynamics [1]. This scheme has been extended towards coherent spin dynamics using the Hartree-Fock truncation [2]. We go beyond this approximation by explicitly including the electron-phonon interaction on a microscopic level [3]. An extension of the equations of motion to entries of the phonon-assisted density matrix is required to account for scattering. They are treated in the Boltzmann-limit as well as beyond this limit leading to microscopic expressions for the spin relaxation times. Furthermore we give an analytical solution of the derived equations by applying the Jaynes-Cummings model [4].
F. Rossi et al., Rev. Mod. Phys. 74 (2002).
U. Rössler; phys. stat. sol. (b) 234 (2002).
C. Lechneret al.; cond-mat/0407358v2 (2004).
E.T Jaynes et al.; Proc. IEEE 51 (1963).