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MA: Fachverband Magnetismus

MA 44: Spininjection / Spin currents in heterostructures

MA 44.3: Talk

Thursday, March 10, 2016, 15:30–15:45, H31

Electrical Spin Injection into an Inverted 2DEG Structure — •Martin Buchner, Thomas Kuczmik, Martin Oltscher, Mariusz Ciorga, Josef Loher, Dieter Schuh, Tobias Korn, Christian Schüller, Dominique Bougeard, Dieter Weiss, and Christian Back — Department of Physics, Regensburg University, 93053 Regensburg, Germany

In 1990 Datta and Das proposed a novel transistor concept, which utilizes the electron’s spin as a new degree of freedom [1]. The current modulation arises from spin precession, which originates from the Bychkov-Rashba-term of spin-orbit-interaction. One key ingredient for the experimental realization of the device is spin injection into a two-dimensional electron gas (2DEG), which turned out to be a challenging task.

In this study, we demonstrate spin injection into a high mobility 2DEG, investigated by means of scanning Kerr microscopy at the cleaved edge of the sample. In detail, we investigate samples with the 2DEG confined at an (Al,Ga)As/GaAs interface; ferromagnetic (Ga,Mn)As contacts are used as spin aligners. Former investigations on these structures have shown a strong enhancement of the nonlocal voltage signal for certain bias conditions [2]. We probe the spatial distribution of the spins with the aid of a diode laser directly underneath the injecting contact. Hanle depolarization gives a measure for the spin lifetimes.

[1] S. Datta, B. Das, Appl. Phys. Lett. 56, 665 (1990).

[2] M. Oltscher et al., Phys. Rev. Lett. 113, 236602 (2014).