Magneto-resistance studies on evenly curved Hall bars in InGaAs/GaAs-microtubes

Abstract

We present transport measurements on evenly curved two‐dimensional electron systems in InGaAs/GaAs‐microtubes. The method of self‐rolling strained semiconductor double layers enables us to build tubes with tuneable radii. With an optimized epitaxial layer design we fabricate InGaAs/GaAs‐microtubes containing a high‐mobility two‐dimensional electron system. A special lithographic procedure enables us to roll up Hall bars with four voltage probes. In a magnetic field the component perpendicular to the 2‐DES plane is strongly modulated. We discuss measurements on rolled up Hall bars with current direction parallel to the axis of the microtube, i.e. the modulation direction of the perpendicular magnetic field component is transversal to the Hall bar. By rotating the tube we are able to adjust this modulation between the voltage probes on opposite sides of the Hall bar. We find that the Hall resistance is given by the average perpendicular magnetic field component and shows a sinusoidal dependency for different rotation angles.