Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Spintronics / Magnetic Semiconductors / Transport

HL 91.13: Poster

Thursday, March 29, 2012, 16:00–19:00, Poster D

Magneto Thermopower Measuremtents on Rolled-Up 2DEGs — •Gunnar Schneider, Matthias Schmidt, David Sonnenberg, Christian Heyn, and Wolfgang Hansen — Institut fuer Angewandte Physik, Universitaet Hamburg, 20355 Hamburg, Germany

We present magneto thermopower measurements on an evenly curved two-dimensional electron gas (2DEG). The 2DEG is confined in a rolled-up GaAs/AlGaAs high electron mobility heterostructure (HEMT). The HEMT is grown by molecular beam epitaxy and, after a suspension step, it rolls up by the relaxation of strain that is intentionally introduced in the HEMT during the growth. Under a magnetic field, the 2D electronic density of states condensates into the Landau levels (LL). The number of filled LLs depends on the strength of the magnetic field component perpendicular to the 2DEG plane. Thus in a rolled-up 2DEG, where the field component is sinusoidally modulated, the density of states changes along the perimeter of the roll. We rotate the rolled up structure in the magnetic field and show the dependence of the diagonal and the off-diagonal (Nernst-Ettinghausen) magneto thermopower on the rotation angle.