Heterostructures containing high-mobility two-dimensional electron gas were rolled into freestanding helically shaped contacted Hall bars. Magnetotransport measurements in these structures at high magnetic fields revealed minima in the longitudinal magnetoresistance corresponding to integer and fractional filling factors. A strong asymmetry of the longitudinal magnetoresistance with respect to the external magnetic field direction was observed. For this new type of structures, an edge state picture was considered, and calculations based on the Landauer-Büttiker formalism are performed.

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