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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.46: Poster

Donnerstag, 17. März 2011, 18:00–21:00, P4

Transport properties of InAs spin-filter cascades in magnetic fields of different directions and strengths — •Hauke Lehmann, Till Benter, Alexander Buhr, and Jan Jacob — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg

We present a three-terminal all-semiconductor nanostructure fabricated from an InAs heterostructure, which separates an unpolarized current into two oppositely spin-polarized currents of equal magnitude by the intrinsic spin Hall effect. If this device is fed with an already spin-polarized current, the conductances of its two outputs are different enabling all-electrical detection of the spin polarization in two-stage spin-filter cascades [1]. The transport measurements are conducted at millikelvin temperatures in a DC-biased lock-in technique. Magnetic fields perpendicular to the two-dimensional electron system introduce a Lorenz force that allows inference on the strength of the intrinsic spin Hall effect. In-plane fields normal to the direction of the electrons’ motion change the spin-orbit coupling. If the field is applied normal to the center wire that connects the two filter stages, the spin precession length is changed leading to oscillations in the conductance fractions of the second filter’s outputs [2]. By applying the field normal to the input wire the separation of spin-up and spin-down electrons in this wire can be tuned.

[1] J. Jacob, G. Meier, S. Peters, T. Matsuyama, U. Merkt, A. Cummings, R. Akis, and D. Ferry. J. Appl. Phys. 105, 093714 (2009).

[2] P. Brusheim and H. Q. Xu, arXiv: 0810.2186v2 (2009).