Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 17: Poster Ib

HL 17.22: Poster

Friday, March 4, 2005, 16:30–19:00, Poster TU F

Magneto transport measurements on overgrown cleaved edge heterostructures in hallbar-geometry — •Markus Lermer, Elisabeth Reinwald, Werner Wegscheider, and Dieter Weiss — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg

We present new methods to pattern and characterise overgrown cleaved edge (CE) heterostructures. By means of a novel sandwich technique a typically 6µ m wide hallbar can be created on the edge of the less than 100µ m wide cleavage-plane. The two-dimensional electron system (2DES) on the CE-plane is contacted by low resistive ohmic finger-contacts. This 4-point geometry allows for the first time direct measurement of the Hall- and longitudinal resistivity components of the 2DES on the cleavage plane. Due to the underlying superlattice the system is density modulated in a direction parallel to the current flow, and shows pronounced magneto resistance oscillations, which can be assigned to the various Fermicontours of a 1D- modulated system. The wet chemical transfer of linepatterns, e-beam written in self assembled monolayers, creates an additional modulation perpendicular to the current flow, so that a 2D-modulated electron system with small unit cell can be realised.