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HL: Fachverband Halbleiterphysik
HL 43: Spintronics (joint session HL/TT)
HL 43.1: Vortrag
Donnerstag, 15. März 2018, 15:00–15:15, EW 201
Anisotropic Spin Diffusion and Spin Helix Dynamics in a CdTe Quantum Well — •Felix Passmann1, Sergiu Anghel1, Alexander Valerievich Poshakinskiy2, Sergey Anatolyevich Tarasenko2, Alan Douglas Bristow3, and Markus Betz1 — 1Experimentelle Physik 2, Technische Universität Dortmund, Otto-Hahn-Straße 4a, D-44227 Dortmund, Germany — 2Ioffe Institute, St. Petersburg 194021, Russia — 3Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506-6315, USA
In the recent past various experiments conducted on zinc-blende type III-V semiconductor quantum wells like GaAs have revealed the dynamics of persistent electron spin helices. However, similar investigations in a doped CdTe single quantum well remained unexplored. Here, we employ ultrafast two-color Kerr rotation spectroscopy to study the spatio-temporal evolution of a photo-excited spin distribution into a long living spin helix (SH). The evolution is governed by the spin-orbit interaction related to bulk and structural inversion asymmetries which manifests as an effective magnetic field. We directly extract the Dresselhaus and Rashba contributions via the coherent spin precession of the diffusing electrons. Further investigations of the SH evolution in the presence of in-plane magnetic fields reveal a so far unseen and theoretically unexpected behavior that we attribute to spatial and temporal gradients of the electron density. The experiments are well supported by corresponding theoretical simulations.