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HL: Fachverband Halbleiterphysik

HL 4: III-V semiconductors: mainly wells and surfaces

HL 4.2: Vortrag

Montag, 11. März 2013, 09:45–10:00, H15

Spin dynamics in high-mobility (110) GaAs-based quantum wells — •Roland Völkl¹, Tobias Korn¹, Markus Schwemmer¹, Michael Griesbeck¹, Sergey Tarasenko², Dieter Schuh¹, Werner Wegscheider³, and Christian Schüller¹ — ¹Institut für Experimentelle und Angewandte Physik, Universität Regensburg — ²A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia — ³ETH Zurich, Switzerland

Here, we present a study of electron spin dynamics in symmetrical, high mobility (110)-grown, GaAs-based quantum wells. The Hanle-MOKE method is used to determine the spin lifetime and the spin polarization of electrons. These properties are studied regarding to changing parameters like temperature or pump power. Additionally the electron density can be tuned using the optical gating technique. Samples with a quantum well width of 20 nm and 30 nm are investigated. In the 30 nm quantum well the Bir-Aronov-Pikus mechanism is dominating, in the investigated temperature range between 4 and 60 K therefore high excitation intensity leads to a faster decay of electron spins. In the 20 nm quantum well this behavior is found at temperatures above 30 K. Below this temperature the Dyakonov-Perel mechanismus dominates. This results in an increase of the spin lifetime for increasing excitation intensities. Financial support by the DFG via SFB 689 and SPP 1285 is gratefully acknowledged.