Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 28: Transport properties

HL 28.3: Vortrag

Dienstag, 26. Februar 2008, 10:00–10:15, ER 164

Electron transmission through magnetic barriers displaced in B-space — Stefan Hugger, •Mihai Cerchez, Hengyi Xu, and Thomas Heinzel — Heinrich-Heine Universität, 40225 Düsseldorf

An inhomogeneous magnetic barrier was created in a Hall bar defined in a GaAs-AlGaAs two-dimensional electron gas, by the stray field present under the edge of a dysprosium magnetic film evaporated on top of the structure [1]. Tilting the sample by small angles around the position in which the field is parallel to the Hall bar in the current direction, one superimposes the perpendicular homogenous component of the applied field, and so shifts the magnetic barrier in B-space, while the magnetic barrier height remains constant to a good approximation. While the magnetic barrier is closed, we show that this experiment changes the balance between different mechanisms of transmission across the magnetic barrier, namely edge orbits, snake orbits and scattering. This produces a minimum in the resistance variation with the perpendicular homogenous field component, position of which depends on the height of the magnetic barrier [2]. The process is simulated with a Landauer-Büttiker model [3] with experimentally determined parameters. The simulations produce excellent agreement to the experiment.

[1] M. Cerchez et al, Phys. Rev. B 75, 035341 (2007)

[2] S. Hugger et al, arXiv:0708.2032, (2007)

[3] M. Büttiker, Phys. Rev. Lett. 57, 1761 (1986)