Hall field induced resistance oscillations by designed random obstacle arrays

Hall field induced resistance oscillations (HIROs) are studied in two-dimensional electron gases with resistivities dominated by scattering at identical but randomly distributed circular obstacles with hard walls. For sufficiently high number densities, these obstacles dominate the HIROs, even though they remain sparse in comparison to the intrinsic scatterers. With increasing obstacle density, we observe a monotonous increase of the HIRO period up to a factor of 2. The results are interpreted in terms of a substantial localization of the Hall field around the designed obstacles, providing an alternative explanation for the HIRO scaling factor <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>γ</a:mi></a:math> in pristine two-dimensional electron gases in terms of spatially varying Hall fields.