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HL: Halbleiterphysik

HL 9: Poster I

HL 9.106: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Magneto-resistance studies on evenly curved Hall bars — •Olrik Schumacher, Miriam Stampe, Christian Heyn, and Wolfgang Hansen — Institut für Angewandte Physik, Jungiusstr. 11, 20355 Hamburg, Germany

We present transport measurements on evenly curved two-dimensional electron systems in InGaAs-microtubes. The method of self-rolling strained semiconductor double layers enables us to build tubes with tuneable radii [1][2]. Using an optimized epitaxial layer design combined with a special lithographic procedure we fabricate GaAs/InGaAs-microtubes with Hall bars containing a two-dimensional electron system (2-DES). When brought into a magnetic field the field component perpendicular to the 2-DES plane is strongly modulated. Transport measurements on such curved Hall bars with current direction along the axis of the microtube will be shown. By rotating the curved Hall bar in the magnetic field one can tune the perpendicular field component such that there is a zero-crossing on the Hall bar. In that case, this field component has opposite sign at the edges of the bar and new electron trajectories like snake orbits are predicted [3]. We discuss ac- as well as dc-measurements in view of the signatures of such orbits.

[1] V. Ya. Prinz et al., Physica E 6 (2000) 828-831

[2] O. Schumacher et al., Appl. Phys. Lett. 86 (2005) 143109

[3] J. E. Müller, Phys. Rev. Lett. 68 (1992) 385-388