Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 31: Poster II

HL 31.4: Poster

Dienstag, 26. Februar 2008, 16:30–19:00, Poster D

Cascade of Y-shaped spin filters in InAs — •Jan Jacob¹, Sebastian Peters¹, Toru Matsuyama¹, Ulrich Merkt¹, Guido Meier¹, Aron Cummings², Richard Akis², and David Ferry² — ¹Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Germany — ²Center for Solid State Electronics Research, Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287-5706

For spintronic devices highly spin-polarized currents are required. While the theoretically predicted values for the injection rate of polarized currents in ferromagnet-semiconductor hybrid devices are low, Y-shaped all-semiconductor structures using the Rashba spin-orbit interaction are predicted to provide a high spin polarization at the outputs of these three-terminal devices [1,2]. The spin-filter effect has been shown by simulations [3] and we will present first measurements here. Quantum-point contacts formed by sidegates are employed to decrease the number of conductance channels in the two-dimensional electron system of an InAs channel inserted into an In_0.75Al_0.25As/In_0.75Ga_0.25As structures. The devices with channel widths down to 100 nm are prepared by electron-beam lithography and reactive ion-etching to generate. Adding a second filter operating as a detector allows an all-electric measurement of the spin polarization. Cascading more filters will lead to a higher degree of polarization.

[1] M. Yamamoto et al., Phys. Rev. B 72, 115321 (2005)

[2] M. Yamamoto et al., Physica E 32, 462 (2006)

[3] A. Cummings et al., Appl. Phys. Lett. 89, 172115 (2006)