Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 35: Spin controlled transport II

HL 35.1: Talk

Wednesday, February 27, 2008, 14:15–14:30, ER 164

Carrier and magnetization dynamics of magnetic resonant tunneling heterostructures — •Christian Ertler and Jaroslav Fabian — Institut für Theoretische Physik, Universität Regensburg, Universitätstrasse 31, D-93040 Regensburg, Germany

The invention and development of magnetic semiconductors has opened up a vast playground for exploiting the possibilities of utilizing the carriers spin in semiconductor electronics. Especially heterostructures made of both magnetic and nonmagnetic layers bring in many opportunities for controlling spin-dependent transport properties [1]. For example, the spin dependent resonant tunneling in magnetic double barrier structures has been exploited to realize high efficient spin valves or spin filtering devices. In this talk the rich dynamics of an asymmetric double barrier system with a ferromagnetic quantum well is theoretically investigated. In such low dimensional semiconductor systems the transport and magnetic characteristics become closely intertwined, since the magnetic state in the quantum well is mediated by the itinerant carriers. The highly nonlinear coupling of the magnetic, electrostatic, and transport properties can lead to astonishing dynamic behaviours. For instance, a robust oscillating current mode accompanied by an oscillating well magnetization shows up at a constant bias voltage. We demonstrate under which conditions this d.c. driven "breathing" magnetization mode occurs and propose different device setups, which should allow for an experimental observation. This work is supported by the SFB-project 689.

[1] J. Fabian et al., Acta Physica Slovaca, 57, 565-907 (2007).