Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 23: Spin controlled transport II

HL 23.7: Vortrag

Dienstag, 27. März 2007, 15:30–15:45, H14

Digital magneto resistance in ferromagnetic resonant tunneling diodes — •Christian Ertler and Jaroslav Fabian — Institute of Theoretical Physics, University of Regensburg, Universitätsstrasse 31, D-93040 Regensburg, Germany

The development of ferromagnetic dilute magnetic semiconductors has paved the way for novel all semiconductor spintronic device concepts. For example, spin dependent resonant tunneling in magnetic double barrier heterostructures with either a ferromagnetic or a paramagnetic quantum well have already been investigated both experimentally and theoretically.

In this talk a novel spintronic device, which consists of two serial connected resonant tunneling diodes, is proposed. One diode is nonmagnetic whereas the other comprises a ferromagnetic emitter and quantum well. Using a selfconsistent coherent transport model we show that the current-voltage characteristic of the ferromagnetic diode can be strongly modulated by changing the relative orientation of the magnetizations in the emitter and quantum well, respectively. By a continuous change of the relative magnetization angle the total resistance exhibits a discrete jump realizing digital magneto resistance. The interplay between the emitter's Fermi energy level and the relative magnetization orientations allows to tailor the current voltage characteristics of the ferromagnetic diode from ohmic to negative differential resistance regime at low voltages. The proposed spintronic device might be useful for a very fast detection of magnetically stored information or magnetic random access memory applications.