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HL: Fachverband Halbleiterphysik

HL 19: Spin-controlled Transport I

HL 19.1: Vortrag

Dienstag, 23. März 2010, 09:30–09:45, H14

Sub-ns electrical spin control in a diluted magnetic semiconductor quantum well — •Yuansen Chen¹, Maciej Wiater², Grzegorz Karczewski², Tomasz Wojtowicz², and Gerd Bacher¹ — ¹Werkstoffe der Elektrotechnik and CeNIDE, Universität Duisburg-Essen, Bismarkstr.81,47057, Duisburg, Germany — ²nstitute of Physics, Polish Academy of Science, Al. Lotnikow 32/46 02-668 Warsaw, Poland

To gain control over the spin degree of freedom is a key issue in semiconductor spintronics. We present an approach to electrically control spins on a sub-ns time scale and on a micrometer length scale in a diluted magnetic semiconductor quantum well (DMS QW). Microscale Au coils are defined atop a CdMnTe/CdMgTe DMS QW and by introducing a short current pulse through the coil, a local magnetic field can be generated enabling an electrical control of Mn2+ spin dynamics in the DMS QW. Due to the strong sp-d exchange interaction, the Mn2+ spin dynamics can be effectively probed by means of time- and polarization- resolved micro-photoluminescence measurements. Thanks to our high time-resolution, we are able to clearly separate the field induced spin alignment and the Mn2+ spin heating process . At zero external field the Mn2+ spin polarization can be switched on a time-scale of several hundred picoseconds, i.e. clearly below typical time scales expected for spin-lattice relaxation . Applying an external field of 100 mT, an additional slow component appears with typical time constants in the few 100 ns regime.