Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 97: Spintronics (joint session HL/TT)

TT 97.7: Vortrag

Donnerstag, 15. März 2018, 16:45–17:00, EW 201

Gate-controllable large magnetoresistance in a 2DES based spin valve device — •Franz Eberle, Martin Oltscher, Thomas Kuczmik, Andreas Bayer, Dieter Schuh, Dominique Bougeard, Mariusz Ciorga, and Dieter Weiss — Universität Regensburg, Regensburg, Germany

The realization of sFET like devices requires the presence of large local spin signals, which can be tuned by an electric field. In typical semiconductor structures, however, values of the magnetoresistance (MR) of only up to 1% have been observed. In this contribution we present the exceptionally large MR we observe in local two-terminal devices with the channel defined within a two-dimensional electron system (2DES) at an inverted GaAs/(Al,Ga)As interface.[1] Spin aligning source and drain contacts are based on a spin Esaki diode structure, consisting of ferromagnetic (Ga,Mn)As and n-doped GaAs. Depending on the applied bias, we observe MR ratios of up to 80%, which correspond to a signal height ΔR in the order of 1kΩ. We tune these large local signals by an electric gating scheme which, contrary to typical sFET proposals, is not based on the manipulation of spins due to the spin-orbit coupling. Instead, we use gates placed outside the current path to control confinement of spins in the region between the leads. With this method we can tune the MR in these devices by up to 14%.

The work was supported by the German Science Foundation through the project SFB 689.

[1] M. Oltscher et al., Nature Communications 8, 1807 (2017)